Physics – Waves Questions for CBSE Class 11th

A transverse wave is represented by the equation y = y 0 sin 2 π λ ( vt − x ) For what value of λ , the maximum particle velocity equal to two times the wave velocity

Two waves having the intensities in the ratio of 9 : 1 produce interference. The ratio of maximum to the minimum intensity, is equal to

The equation of a travelling wave is given by y = 0 .5 sin ( 20 x − 400 t ) where x and y are in meter and t is in second. The velocity of the wave is

When two sound waves with a phase difference of π / 2 , and each having amplitude A and frequency ω , are superimposed on each other, then the maximum amplitude and frequency of resultant wave is

A source of sound S is moving with a velocity 50m/s towards a stationary observer. The observer measures the frequency of the source as 1000 Hz. What will be the apparent frequency of the source when it is moving away from the observer after crossing him ? The velocity of sound in the medium is 350 m/s

A Siren emitting sound of frequency 800 Hz is going away from a static listener with a speed of 30 m/s, frequency of the sound to be heard by the listener is (take velocity of sound as 330 m/s)

The intensity of sound from a radio at a distance of 2 metres from its speaker is 1 × 0 − 2 μ   W ​ / ​ m 2 . The intensity at a distance of 10 meters would be

The power of a sound from the speaker of a radio is 20 mW. By turning the knob of the volume control, the power of the sound is increased to 400 mW. The power increase in decibels as compared to the original power is

Two identical stringed instruments have frequency 100 Hz. If tension in one of them is increased by 4% and they are sounded together then the number of beats in one second is

A metal wire of diameter 1.5 mm is held on two knife edges separated by a distance 50 cm the tension in the wire is 100 N the wire vibrating with its fundamental frequency and vibrating tuning fork together produces 5 beats per second. The tension in the wire is then reduced to 81 N, when the two are excited, beats are heard at the same rate. Calculate frequency of the fork.

A transverse wave described by equation y = 0.02 sin x + 30 t (where x and t are in metre and sec. respectively) is travelling along a wire of area of cross-section 1  mm 2 and density 8  g / cc . What is the tension in the string? (in Newtons)

The displacement y of a wave travelling in the x-direction is given by y = 10 − 4 sin    600 t − 2 x + π 3 metres, where x is expressed in metres and t in seconds. The speed of the wave-motion, in ms –1 , is

The phase difference between two waves represented by y 1 = 10 − 6 sin [ 100   t + ( x / 50 ) + 0 .5 ] m y 2 = 10 − 6 cos   [ 100   t + ( x / 50 ) ] m where x is expressed in metres and t is expressed in seconds, is approximately

Two sound waves (expressed in CGS units) given by y 1 = 0 .3 sin 2 π λ ( vt − x ) and y 2 = 0 .4 sin 2 π λ ( vt − x + θ ) interfere. The resultant amplitude at a place where phase difference is π / 2 will be

With what velocity an observer should move relative to a stationary source so that he hears a sound of double the frequency of source

An observer is moving away from source of sound of frequency 100 Hz. His speed is 33 m/s. If speed of sound is 330 m/s, then the observed frequency is

What should be the velocity of a sound source moving towards a stationary observer so that apparent frequency is double the actual frequency (Velocity of sound is v)

Intensity level of a sound of intensity I is 30 dB. The ratio I I 0 is (Where I 0 is the threshold of hearing)

A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 2m and 3m respectively from the source. The ratio of the intensities of the waves at P and Q is

A long uniform steel wire has a diameter of 2.0 mm. what should be the tension in the wire, so that the speed of the transverse wave on it equals the speed of sound at STP (320 m/s) the density of steel is 7800   k g / m 3 .

Two waves travelling in a medium are given by y 1 = 2 sin ( 3 π t − π 2 x ) and y 2 = 4 sin 6 π t − 3 π 2 x , where y 1 ,   y 2 and x are in cm and t in sec the displacement of a particle at x = 1   c m and t = 1   sec is

Two persons A and B each carrying a source of sound of frequency γ , are standing a few meters a part in a quiet field, ‘A’ starts moving towards ‘B’ with a speed of u .If V be the speed of sound then the number of beats heard per second by A will be

Two sound waves of length 9 and 10 meters produces 34 beats in 9 seconds. Find velocity sound.

The ratio of the speed of sound in nitrogen gas to that in helium gas, at 300 K is

Velocity of sound waves in air is 330 m/sec. For a particular sound in air, a path difference of 40 cm is equivalent to a phase difference of 1.6 π . The frequency of this wave is

A man is standing between two parallel cliffs and fires a gun. If he hears first and second echoes after 1.5 s and 3.5s respectively, the distance between the cliffs is (Velocity of sound in air = 340 ms –1 )

When the temperature of an ideal gas is increased by 600 K, the velocity of sound in the gas becomes 3 times the initial velocity in it. The initial temperature of the gas is

A man standing on a cliff claps his hand hears its echo after 1 sec. If sound is reflected from another mountain and velocity of sound in air is 340 m/sec. Then the distance between the man and reflection point is

Sound velocity is maximum in

The temperature at which the speed of sound in air becomes double of its value at 0 o C is

If v m is the velocity of sound in moist air, v d is the velocity of sound in dry air, under identical conditions of pressure and temperature

It is possible to distinguish between the transverse and longitudinal waves by studying the property of

A medium can carry a longitudinal wave because it has the property of

A source of sound of frequency 600 Hz is placed inside water. The speed of sound in water is 1500 m/s and in air is 300 m/s. The frequency of sound recorded by an observer who is standing in air is

Sound waves in air are

Which of the following is not the transverse wave

A big explosion on the moon cannot be heard on the earth because

A wave of frequency 500 Hz has velocity 360 m/sec. The distance between two nearest points 60° out of phase, is

Sound waves of wavelength greater than that of audible sound are called

The intensity of sound increases at night due to

Which of the following do not require medium for transmission

Ultrasonic signal sent from SONAR returns to it after reflection from a rock after a lapse of 1 sec. If the velocity of ultrasound in water is 1600 ms –1 , the depth of the rock in water is

Equation of a progressive wave is given by y = 0 .2 cosπ 0 .04 t + . 02 x − π 6 The distance is expressed in cm and time in second. What will be the minimum distance between two particles having the phase difference of π /2

The relation between time and displacement for two particles is given by y 1 = 0 .06 sin 2 π ( 1 .04 t + φ 1 ) , y 2 = 0 .03 sin 2 π ( 1 .04 t + φ 2 ) The ratio of the intensity of the waves produced by the vibrations of the two particles will be

A plane wave is represented by x = 1 .2 sin ( 314   t + 12 .56 y ) Where x and y are distances measured along in x and y direction in meters and t is time in seconds. This wave has

Two monoatomic ideal gases 1 and 2 of molecular masses m 1 and m 2 respectively are enclosed in separate containers kept at the same temperature. The ratio of the speed of sound in gas 1 to that in gas 2 is given by

A travelling wave in a stretched string is described by the equation y = Asin ( kx − ωt ) . The maximum particle velocity is

The equation of a plane progressive wave is given by y = 0 .025 sin ( 100 t + 0 .25 x ) . The frequency of this wave would be

There is a destructive interference between the two waves of wavelength λ coming from two different paths at a point. To get maximum sound or constructive interference at that point, the path of one wave is to be increased by

If the ratio of amplitude of two waves is 4 : 3. Then the ratio of maximum and minimum intensity will be

Two tuning forks have frequencies 450 Hz and 454 Hz respectively. On sounding these forks together, the time interval between successive maximum intensities will be

On sounding tuning fork A with another tuning fork B of frequency 384 Hz, 6 beats are produced per second. After loading the prongs of A with some wax and then sounding it again with B, 4 beats are produced per second. What is the frequency of the tuning fork A

Maximum number of beats frequency heard by a human being is

Two waves of lengths 50 cm and 51 cm produced 12 beats per second. The velocity of sound is

A wave represented by the given equation y = acos ( kx − ω   t ) is superposed with another wave to form a stationary wave such that the point x = 0 is a node. The equation for the other wave is

At a certain instant a stationary transverse wave is found to have maximum kinetic energy. The appearance of string at that instant is

A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The frequency of the unknown fork is

A steel rod 100 cm long is clamped at its mid-point. The funda-mental frequency of longitudinal vibrations of the rod is given to be 2.53 kHz. What is the speed of sound in steel

To increase the frequency from 100 Hz to 400 Hz the tension in the string has to be changed by

In order to double the frequency of the fundamental note emitted by a stretched string, the length is reduced to 3 4 th of the original length and the tension is changed. The factor by which the tension is to be changed, is

The sound carried by air from a sitar to a listener is a wave of the following type

A device used for investigating the vibration of a fixed string or wire is

The length of two open organ pipes are l and ( l + Δl ) respectively. Neglecting end correction, the frequency of beats between them will be approximately (Here v is the speed of sound)

An open pipe of length l vibrates in fundamental mode. The pressure variation is maximum at

An open pipe is suddenly closed at one end with the result that the frequency of third harmonic of the closed pipe is found to be higher by 100 Hz than fundamental frequency of open pipe, then the fundamental frequency of open pipe is:

Apparatus used to find out the velocity of sound in gas is

In a closed organ pipe the frequency of fundamental note is 50 Hz. The note of which of the following frequencies will not be emitted by it

Two closed organ pipes of length 100 cm and 101 cm 16 beats in 20 sec. When each pipe is sounded in its fundamental mode calculate the velocity of sound

A source of sound is moving with constant velocity of 20 m/s emitting a note of frequency 1000 Hz. The ratio of frequencies observed by a stationary observer while the source is approaching him and after it crosses him will be (Speed of sound v = 340 m/s)

A source of sound emits waves with frequency f Hz and speed V m/sec. Two observers move away from this source in opposite directions each with a speed 0.2 V relative to the source. The ratio of frequencies heard by the two observers will be

A source and an observer move away from each other with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz, then actual frequency of the source is (velocity of sound in air = 340 m/s)

A source of sound of frequency 500 Hz is moving towards an observer with velocity 30 m/s. The speed of sound is 330 m/s. the frequency heard by the observer will be

A person carrying a whistle emitting continuously a note of 272 Hz is running towards a reflecting surface with a speed of 18 km/hour. The speed of sound in air is 345 ms − 1 . The number of beats heard by him is

A source and an observer are moving towards each other with a speed equal to v 2 where v is the speed of sound. The source is emitting sound of frequency n. The frequency heard by the observer will be

Tone A has frequency of 240 Hz. Of the following tones, the one which will sound least harmonious with A is

Ten tuning forks are arranged in increasing order of frequency in such a way that any two nearest tuning forks produce 4 beats/sec. The highest frequency is twice of the lowest. Possible highest and the lowest frequencies are

An observer moves towards a stationary source of sound with a speed 1/5 th of the speed of sound. The wavelength and frequency of the source emitted are λ and f respectively. The apparent frequency and wavelength recorded by the observer are respectively

A racing car moving towards a cliff, sounds its horn. The driver observes that the sound reflected from the cliff has a pitch one octave higher than the actual sound of the horn. If v is the velocity of sound, then the velocity of the car is

Two pulses in a stretched string whose centres are initially 8 cm apart are moving towards each other as shown in the figure. The speed of each pulse is 2 cm/s. After 2 seconds, the total energy of the pulses will be

A string of length L and mass M hangs freely from a fixed point. Then the velocity of transverse waves along the string at a distance x from the free end is

A man is standing on a railway platform listening to the whistle of an engine that passes the man at constant speed without stopping. If the engine passes the man at time t 0 . How does the frequency f of the whistle as heard by the man changes with time

A tuning fork of frequency 340 Hz is vibrated just above the tube of 120 cm height. Water is poured slowly in the tube. What is the minimum height of water necessary for the resonance (speed of sound in the air = 340 m/sec)

Two speakers connected to the same source of fixed frequency are placed 2.0 m apart in a box. A sensitive microphone placed at a distance of 4.0m from their midpoint along the perpendicular bisector shows maximum response. The box is slowly rotated until the speakers are in line with the microphone. The distance between the midpoint of the speakers and the microphone remains unchanged. Exactly five maximum responses are observed in the microphone in doing this. The wavelength of the sound wave is

If reflection takes place from optically rarer medium and denser medium the change in phase respectively is

Transverse wave are generated in two uniform steel wires A & B of same length but having diameters 10 − 3 m and 0.5 × 10 − 3 m respectively, by attaching their free end to a vibrating source of frequency 500 Hz. Find the ratio of the wavelengths if they are stretched with the same tension.

The transverse displacement of a string fixed at both ends is given by − y ,   x are in meter y = 0.06 sin 2 π x 3 cos 120 π t and t in sec the length of string is 1.5 m and its mass is 3 × 10 − 3 k g . Find amplitude at point x = 0.5 m .

A car C blowing a horn of frequency 650 Hz is moving at a speed of 25 m/sec on a straight path CP. A person is standing at a point O at a distance of 40 m perpendicular to CP as shown in figure. When car is 30 m away from P, the apparent frequency of sound as heard by the person is ( V s o u d = 345   m / sec )

Third overtone of closed organ pipe is in unison with fourth harmonic of an open pipe. Find the ratio of the lengths of the pipes.

The length of two open organ pipes are l and l + Δ l Δ l < < l , if u is the speed of sound, find the frequency of beats between them

A one metre long (both ends open) organ pipe is kept in a gas that has double the density of air at STP. Assuming the speed of sound in air at STP is 300 m/s, the frequency difference between the fundamental and second harmonic of this pipe is Hz

Two coherent sources of sound, S 1 and S 2 , produce sound waves of the same wavelength, λ = 1 m, in phase. S 1 and S 2 are placed 1.5 m apart (see fig). A listener, located at L, directly in front of S 2 finds that the intensity is at a minimum when he is 2 m away from S 2 . The listener moves away from S 1 , keeping his distance from S 2 fixed. The adjacent maximum of intensity is observed when the listener is at a distance d from S 1 . Then, d is :

For a person with normal hearing the faintest sound that can be heard at a frequency of 400Hz has a pressure amplitude of about 6 × 10 − 5  N/m 2 . Calculate the corresponding intensity in W / m 2 . Take speed of sound in air as 344m/s and density of air 1.2  kg / m 3

An open pipe is in resonance in its 2 nd harmonic with tuning fork of frequency f 1 . Now it is closed at one end. If the frequency of the tuning fork is increased slowly from f 1 then again a resonance is obtained with a frequency f 2 . If in this case the pipe vibrates n th harmonics then

Two sound waves of slightly different frequency have amplitude ratio 11/9. What is the difference of sound levels in decibels of maximum and minimum intensities heard at a point?

A sonometer wire of length 1.5m is made of steel. The tension in it produce an elastic strain of 1%. What is the fundamental frequency of transverse vibrations in Hz if density and young’s modulus of steel are 7.7 × 10 3  kg / m 3 and 15.4 × 10 11  N / m 2 respectively? 2 = 1.414 , 3 = 1.732 , 5 = 2.236

The relation between frequency ‘n’ wavelength ‘ λ ’ and velocity of propagation ‘v’ of wave is

Ultrasonic, Infrasonic and audible waves travel through a medium with speeds V u ,   V i and V a respectively, then

The distance between two consecutive crests in a wave train produced in a string is 5 cm. If 2 complete waves pass through any point per second, the velocity of the wave is

When a sound wave of frequency 300 Hz passes through a medium the maximum displacement of a particle of the medium is 0.1 cm. The maximum velocity of the particle is equal to

A man sets his watch by a whistle that is 2 km away. How much will his watch be in error. (speed of sound in air 330 m/sec)

A hospital uses an ultrasonic scanner to locate tumours in a tissue. The operating frequency of the scanner is 4.2 MHz. The speed of sound in a tissue is 1.7 km-s –1 . The wavelength of sound in the tissue is close to

The minimum audible wavelength at room temperature is about

If the density of Oxygen is 16 times that of Hydrogen, what will be the ratio of their corresponding velocities of sound waves

What will be the wave velocity, if the radar gives 54 waves per min and wavelength of the given wave is 10 m

The type of waves that can be propagated through solid is

If at same temperature and pressure, the densities for two diatomic gases are respectively d 1 and d 2 , then the ratio of velocities of sound in these gases will be

If wavelength of a wave is λ = 6000 Å . Then wave number will be

A man stands in front of a hillock and fires a gun. He hears an echo after 1.5 sec. The distance of the hillock from the man is (velocity of sound in air is 330 m/s)

Find the frequency of minimum distance between compression & rarefaction of a wire. If the length of the wire is 1m & velocity of sound in air is 360 m/s

The waves in which the particles of the medium vibrate in a direction perpendicular to the direction of wave motion is known as

Ultrasonic waves are those waves

The equation of a progressive wave is given by y = asin ( 628 t − 31 .4 x ) If the distances are expressed in cms and time in seconds, then the wave velocity will be

The particles of a medium vibrate about their mean positions whenever a wave travels through that medium. The phase difference between the vibrations of two such particles

With the propagation of a longitudinal wave through a material medium, the quantities transmitted in the propagation direction are

The displacement y of a particle in a medium can be expressed as: y = 10 − 6 sin ( 100 t + 20 x + π / 4 ) m , where t is in second and x in meter. The speed of wave is

A plane progressive wave is represented by the equation y = 0 .1 sin 200 πt − 20 πx 17 where y is displacement in m, t in second and x is distance from a fixed origin in meter. The frequency, wavelength and speed of the wave respectively are

A transverse progressive wave on a stretched string has a velocity of 10 ms -1 and a frequency of 100 Hz. The phase difference between two particles of the string which are 2.5 cm apart will be

Equation of a progressive wave is given by y = a   sinπ   t 2 − x 4   , where t is in seconds and x is in meters. The distance through which the wave moves in 8 sec is (in meter)

Equation of motion in the same direction are given by y 1 = 2 asin ( ωt − kx ) and y 2 = 2 asin ( ωt − kx − θ ) The amplitude of the medium particle will be

If the equation of transverse wave is Y = 2 sin ( kx − 2 t ) , then the maximum particle velocity is

If two waves of same frequency and same amplitude respectively, on superimposition produced a resultant disturbance of the same amplitude, the waves differ in phase by

The superposition takes place between two waves of frequency f and amplitude a. The total intensity is directly proportional to

If two waves having amplitudes 2A and A and same frequency and velocity, propagate in the same direction in the same phase, the resulting amplitude will be

The displacement of a particle is given by x = 3 sin ( 5 π   t ) + 4 cos ( 5 π   t ) The amplitude of the particle is

Two waves y 1 = A 1 sin ( ωt − β 1 ) , y 2 = A 2 sin ( ωt − β 2 ) Superimpose to form a resultant wave whose amplitude is

Two waves having equations x 1 = asin ( ω   t + φ 1 ) , x 2 = asin   ( ω   t + φ 2 ) If in the resultant wave the frequency and amplitude remain equal to those of superimposing waves. Then phase difference between them is

Two tuning forks when sounded together produced 4 beats/sec. The frequency of one fork is 256. The number of beats heard increases when the fork of frequency 256 is loaded with wax. The frequency of the other fork is

A tuning fork sounded together with a tuning fork of frequency 256 emits two beats. On loading the tuning fork of frequency 256, the number of beats heard are 1 per second. The frequency of tuning fork is

A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is

Two waves y = 0 .25 sin 316   t and y = 0 .25 sin 310   t are travelling in same direction. The number of beats produced per second will be

Beats are produced with the help of two sound waves of amplitudes 3 and 5 units. The ratio of maximum to minimum intensity in the beats is

Two sound waves of slightly different frequencies propagating in the same direction produce beats due to

The wavelength of a particle is 99 cm and that of other is 100 cm. Speed of sound is 396 m/s. The number of beats heard per sec is

A standing wave is represented by Y = A sin ( 100 t ) cos ( 0 .01 x ) where Y and A are in millimetre, t is in seconds and x is in metre. The velocity of wave is

A sound source of frequency 170 Hz is placed near a wall. A man walking from a source towards the wall finds that there is a periodic rise and fall of sound intensity. If the speed of sound in air is 340 m/s the distance (in metres) separating the two adjacent positions of minimum intensity is

The distance between the nearest node and antinode in a stationary wave is

In stationary wave

At nodes in stationary waves

In stationary waves all particles between two nodes pass through the mean position

If vibrations of a string are to be increased by a factor of two, then tension in the string must be made

A stretched string of length l, fixed at both ends can sustain stationary waves of wavelength λ , given by

If you set up the seventh harmonic on a string fixed at both ends, how many nodes and antinodes are set up in it

In Melde’s experiment in the transverse mode, the frequency of the tuning fork and the frequency of the waves in the strings are in the ratio

The first overtone of a stretched wire of given length is 320 Hz. The first harmonic is :

The fundamental frequency of a sonometre wire is n. If its radius is doubled and its tension becomes half, the material of the wire remains same, the new fundamental frequency will be

The first overtone in a closed pipe has a frequency

If the velocity of sound in air is 350 m/s. Then the fundamental frequency of an open organ pipe of length 50 cm, will be

Fundamental frequency of an open pipe of length 0.5 m is equal to the frequency of the first overtone of a closed pipe of length l. The value of l c is (m)

If fundamental frequency of closed pipe is 50 Hz then frequency of 2 nd overtone is

The frequency of fundamental tone in an open organ pipe of length 0.48 m is 320 Hz. Speed of sound is 320 m/sec. Frequency of fundamental tone in closed organ pipe will be

An organ pipe, open from both ends produces 5 beats per second when vibrated with a source of frequency 200 Hz. The second harmonic of the same pipes produces 10 beats per second with a source of frequency 420 Hz. The frequency of source is

In a resonance pipe the first and second resonances are obtained at depths 22.7 cm and 70.2 cm respectively. What will be the end correction

A source of sound of frequency 450 cycles/sec is moving towards a stationary observer with 34 m/sec speed. If the speed of sound is 340 m/sec, then the apparent frequency will be

The wavelength is 120 cm when the source is stationary. If the source is moving with relative velocity of 60 m/sec towards the observer, then the wavelength of the sound wave reaching to the observer will be (velocity of sound = 330 m/s)

Two passenger trains moving with a speed of 108 km/hour cross each other. One of them blows a whistle whose frequency is 750 Hz. If sound speed is 330 m/s, then passengers sitting in the other train, after trains cross each other will hear sound whose frequency will be

A table is revolving on its axis at 5 revolutions per second. A sound source of frequency 1000 Hz is fixed on the table at 70 cm from the axis. The minimum frequency heard by a listener standing at a distance from the table will be nearly (speed of sound = 352 m/s)

Doppler shift in frequency does not depend upon

A sound source is moving towards a stationary observer with 1/10 of the speed of sound. The ratio of apparent to real frequency is

A source of frequency 150 Hz is moving in the direction of a person with a velocity of 110 m/s. The frequency heard by the person will be (speed of sound in medium = 330 m/s)

The speed of sound in air at a given temperature is 350 m/s. An engine blows whistle at a frequency of 1200 cps. It is approaching the observer with velocity 50 m/s. The apparent frequency in cps heard by the observer will be

A motor car blowing a horn of frequency 124 vib/sec moves with a velocity 72 km/hr towards a tall wall. The frequency of the reflected sound heard by the driver will be (velocity of sound in air is 330 m/s)

A source of sound emitting a note of frequency 200 Hz moves towards an observer with a velocity v. If the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is

A whistle giving out 450 Hz approaches a stationary observer at a speed of 33 m/s. The frequency heard by the observer in Hz is (speed of sound is 330 m/s)

A boy is walking away from a wall towards an observer at a speed of 1 metre/sec and blows a whistle whose frequency is 680 Hz. The number of beats heard by the observer per second is (Velocity of sound in air = 340 metres/sec

The driver of a car travelling with speed 30 metres per second towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 metres per second, the frequency of the reflected sound as heard by the driver is

Two sirens situated one kilometer apart are producing sound of frequency 330 Hz. An observer starts moving from one siren to the other with a speed of 2 m/s. If the speed of sound be 330 m/s, what will be the beat frequency heard by the observer

A source is moving towards an observer with a speed of 20 m/s and having frequency of 240 Hz. The observer is now moving towards the source with a speed of 20 m/s. Apparent frequency heard by observer, if velocity of sound is 340 m/s, is

A siren emitting sound of frequency 500 Hz is going away from a static listener with a speed of 50 m/sec. The frequency of sound to be heard, directly from the siren, is

A car sounding a horn of frequency 1000 Hz passes an observer. The ratio of frequencies of the horn noted by the observer before and after passing of the car is 11 : 9. If the speed of sound is v, the speed of the car is

A small source of sound moves on a circle as shown in the figure and an observer is standing on O. Let n 1 , n 2 and n 3 be the frequencies heard when the source is at A, B and C respectively. Then

A source of sound of frequency 256 Hz is moving rapidly towards a wall with a velocity of 5 m/s. The speed of sound is 330 m/s. If the observer is between the wall and the source, then beats per second heard will be

The intensity of sound wave while passing through an elastic medium falls down by 10% as it covers one metre distance through the medium. If the initial intensity of the sound wave was 100 decibels, its value after it has passed through 3 metre thickness of the medium will be

When we hear a sound, we can identify its source from

The amplitude of two waves are in ratio 5 : 2. If all other conditions for the two waves are same, then what is the ratio of their energy densities

Each of the properties of sound listed in column A primarily depends on one of the quantities in column B. Choose the matching pairs from two columns Column A Column B Pitch Waveform Quality Frequency Loudness Intensity

In the experiment for the determination of the speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode, with a tuning fork is 0.1 m. when this length is changed to 0.35 m, the same tuning fork resonates with the first overtone. Calculate the end correction

Two waves are having sinusoidal waveforms have different wavelengths and different amplitude. They will be having (assume frequency same)

In a large room, a person receives direct sound waves from a source 120 metres away from him. He also receives waves from the same source which reach him, being reflected from the 25 metre high ceiling at a point halfway between them. The two waves interfere constructively for wavelength of

The ends of a stretched wire of length L are fixed at x = 0 and x = L. In one experiment, the displacement of the wire is y 1 = Asin ( πx / L ) sinωt and energy is E 1 , and in another experiment its displacement is y 2 = Asin ( 2 πx / L ) sin 2 ωt and energy is E 2 . Then

Two cars are moving on two perpendicular roads towards a crossing with uniform speeds of 72 km/hr and 36 km/hr. If first car blows horn of frequency 280 Hz, then the frequency of horn heard by the driver of second car when line joining the cars make 45° angle with the roads; will be

A source producing sound of frequency 170 Hz is approaching a stationary observer with a velocity 17 ms –1 . The apparent change in the wavelength of sound heard by the observer is (speed of sound in air = 340 ms –1 )

41 forks are so arranged that each produces 5 beats per sec when sounded with its near fork. If the frequency of last fork is double the frequency of first fork, then the frequencies of the first and last fork are respectively (in Hz)

Two identical straight wires are stretched so as to produce 6 beats per second when vibrating simultaneously. On changing the tension in one of them, the beat frequency remains unchanged. Denoting by T 1 , T 2 , the higher and the lower initial tensions in the strings, then it could be said that while making the above change in tension

An open pipe is in resonance in its 2 nd harmonic with tuning fork of frequency f 1 . Now it is closed at one end. If the frequency of the tuning fork is increased slowly from f 1 then again a resonance is obtained with a frequency f 2 . If in this case the pipe vibrates n th harmonics then

Two loudspeakers L 1 and L 2 driven by a common oscillator and amplifier, are arranged as shown. The frequency of the oscillator is gradually increased from zero and the detector at D records a series of maxima and minima. If the speed of sound is 330 ms –1 then the frequency at which the first maximum is observed is

The displacement due to a wave moving in the positive x-direction is given by y = 1 ( 1 + x 2 ) at time t = 0 and by y = 1 [ 1 + ( x − 1 ) 2 ] at t = 2 seconds, where x and y are in metres. The velocity of the wave in m/s is

The figure shows four progressive waves A, B, C, and D with their phases expressed with respect to the wave A. It can be concluded from the figure that

The displacement of a particle in string stretched in X direction is represented by y. Among the following expressions for y, those describing wave motions are

An earthquake generates both transverse (S) and longitudinal (P) sound waves in the earth. The speed of S waves is about 4.5 km/s and that of P waves is about 8.0 km/s. A seismograph records P and S waves from an earthquake. The first P wave arrives 4.0 min before the first S wave. The epicenter of the earthquake is located at a distance about

The rope shown at an instant is carrying a wave travelling towards right, created by a source vibrating at a frequency n. Consider the following statements I. The speed of the wave is 4 n × ab II. The medium at a will be in the same phase as d after 4 3 n s III. The phase difference between b and e is 3 π 2 Which of these statements are correct

A stone is hung in air from a wire which is stretched over a sonometer. The bridges of the sonometer are L cm apart when the wire is in unison with a tuning fork of frequency N. When the stone is completely immersed in water, the length between the bridges is l cm for re-establishing unison, the specific gravity of the material of the stone is

Which of the following curves represents correctly the oscillation given by y = y 0 sin ( ω   t − φ ) , where 0 0 < φ < 90 0

In Melde’s experiment, the string vibrates in 4 loops when a 50 gram weight is placed in the pan of weight 15 gram. To make the string to vibrates in 6 loops the weight that has to be removed from the pan is

Vibrating tuning fork of frequency n is placed near the open end of a long cylindrical tube. The tube has a side opening and is fitted with a movable reflecting piston. As the piston is moved through 8.75 cm, the intensity of sound changes from a maximum to minimum. If the speed of sound is 350 m/s. Then n is

An observer starts moving with uniform acceleration a toward a stationary sound source emitting a whistle of frequency n. As the observer approaches source, the apparent frequency, heard by the observer varies with time as

Two tuning forks P and Q are vibrated together. The number of beats produced are represented by the straight line OA in the following graph. After loading Q with wax again these are vibrated together and the beats produced are represented by the line OB. If the frequency of P is 341Hz, the frequency of Q will be

A wire of 9 .8 × 10 − 3 kgm − 1 passes over a frictionless light pulley fixed on the top of a frictionless inclined plane which makes an angle of 30° with the horizontal. Masses m and M are tied at the two ends of wire such that m rests on the plane and M hangs freely vertically downwards. The entire system is in equilibrium and a transverse wave propagates along the wire with a velocity of 100 ms –1 . Choose the correct option

A man standing in front of a mountain beats a drum at regular intervals. The rate of drumming is generally increased and he finds that the echo is not heard distinctly when the rate becomes 40 per minute. He then moves nearer to the mountain by 90 m and finds that echo is again not heard when the drumming rate becomes 60 per minute. The distance between the mountain and the initial position of the man is

Two sound sources produce progressive waves given by y 1 = 12 cos ⁡ 100 πt and y 2 = 12 cos ⁡ 102 πt near the ear of an observer. When sounded together, the observer will hear beats. The observed beat frequency (in Hz) is

The ratio of the velocity of sound in hydrogen γ = 7 5 to that in helium γ = 5 3 at the same temperature is

Two identical sinusoidal waves with wave lengths of 3.00 m travel in the same direction at a speed of 2.00 m/s. The second wave originates from the same point as the first, but at a later time. The amplitude of the resultant wave is the same as that of each of the two initial waves. Determine the minimum possible time interval (in sec) between the starting moments of the two waves.

An ideal organ pipe resonates at successive frequencies of 50 Hz, 150 Hz, 250 Hz, etc (speed of sound = 340 m/s) The pipe is

The displacement y of a particle in a medium can be expressed as y=10 -6 sin 100t+20x+ π 4  m where t is in second and x in metre. The speed of the wave is

A travelling wave on a string is given by y = 7.5 sin ( 0.005 x + 12 t + π / 4 ) . Find the displacement and velocity of the particle at a point x = 1   c m t = 1 sec . Take sin ( 12.7 o ) = 0.22 .

When a wave travels in a medium the displacements of particles are given by y = 0.01 sin 2 π ( 2 t − 0.01 x ) where x ,   y are in meter and t in seconds. Find wavelength, wave velocity.

The intensity of sound is 1.0   W / m 2 . Find the intensity level in dB.

Compare the velocities of sound in hydrogen and carbon dioxide

The speed of sound in a gas is V and the root mean square speed of gas molecules is v r m s . If the ratio of the specific heats of gas γ = 1.5 then ratio v / v r m s is

A wire having a linear density of 0.05   g / c m is stretched between two rigid supports with a tension of 4.5 × 10 2 N it is observed that the wire resonance at a frequency of 420 Hz. The next higher frequency at which the wire resonates is 490 Hz. Determine the length of the wire.

A pipe of length 20 cm is open at both ends. Which harmonic mode of the pipe is resonantly excited by a 1700 Hz source? The speed of sound = 340ms −1

Two identical flutes produce fundamental notes of frequency 300 Hz at 27 0 C . If the temp of the air in one flute is increased to 31 0 C . The number of beats heard per second will be

A sonometer wire has a length of 114 cm between two fixed ends, where should two bridges be placed to divide the wire into three segments whole fundamental frequencies are in the ratio 1 : 3 : 4 ?

Consider the situation shown in fig. The wire which has a mass of 4.00g oscillates in its second harmonic and sets the air column in the tube into vibrations in its fundamental mode assuming the speed of sound in air is 340    m / sec then the tension in the wire is N

In the arrangement shown in figure a rectangular pulse and a triangular pulse approaching each other both with the pulse speed 0.5 cm/sec . The resultant pulse at t = 2   sec .

A 40 cm wire having a mass of 3.2 g is stretched between two fixed supports 40.05 cm apart. In its fundamental mode, the wire vibrates at 220 Hz. If the area of cross-section of the wire is 1.0   m m 2 , then young’s modulus of the wire is × 10 11   N / m 2

A heavy ball is suspended from the ceiling of a motor car through a light string. A transverse pulse travels at speed of 60   c m / sec on the string when the car is at rest and 62   c m / sec when the car accelerates on a horizontal road. The acceleration of the car is m / sec 2 .

The Intensity of sound of loudness level 60dB is n × 10 − 4     w a t t / m 2 . Find n.

The wavelength of light coming from a distant galaxy is found to be 0.5% more than that coming from a source on earth, then the velocity of galaxy is × 10 7   m / sec

Speed of a transverse wave on a straight wire (mass 6.0g, length 60 cm) and area of cross-section of wire 1.0   m m 2 is 80   m / sec . If the young’s modulus of wire is 16 × 10 11   N / m 2 , then extension of wire over its natural length is

A one meter long (both ends open) organ pipe is kept in a gas that has triple the density of air at STP. Assuming the speed of sound in air at S.T.P is 300 m/s . The frequency difference between the fundamental and second harmonic of this pipe is

A transverse wave travels on a taut steel wire with velocity of V when tension in it is 2.06 × 10 4 N . When the tension is changed to T , the velocity changed to V / 4 . The value of T is closed to

A pipe open at both ends has a fundamental frequency f in air. The pipe is dipped vertically in water so that half of it is in water. The fundamental frequency of air column is now

Equation of travelling wave on stretched string of linear density 5 g / m is y = 0.03 sin 450 t − 9 x where distance and time are measured in S.I units . The tension in the string is

A wire of length l and Mass per uniform length 6.0 × 10 − 3   k g / m is put under tension of 500 N . Two consecutive frequencies it resonates at are 420 H z and 490 H z . Then l in meters is

A string is clamped at both the ends and it is vibrating in its 4th harmonic. The equation of the stationary wave is y = 0.3 sin 0.157 x c o s 200 π t . The length of the string is

A string of length 1 m and mass 5 g is fixed at both ends. The tension in the string is 8 N . The string is sent into vibration using an external vibrator of frequency 100 Hz . The separation between successive nodes on the string is close to

A small speaker delivers 2 W of audio output at what distance from the speaker will one detect 120 dB intensity sound (Given reference intensity = 10 – 12 W / m 2 )

A string 2 m long and fixed at its ends is driven by a 240 Hz vibrator. The string vibrates in its third harmonic mode. The speed of the wave and its fundamental frequency is

The equation of a wave on string of linear mass density 0.04   k g / m is given by y = 0.02 sin 2 π t 0.04 − x 0.50 . The tension in the string is

The speed of sound in oxygen O 2 at certain temperature is 460   m / sec . The speed of sound in Helium (He) at same temperature will be (assumed both gases to be ideal)

A sonometer wire of length 1.5 m is made of steel the tension in it produces an elastic strain of 1%. What is the fundamental frequency of steel if density and elasticity of steel are 7.7 × 10 3 k g / m 2 and 2.2 × 10 11 N / m 2 respectively ?

Two monoatomic ideal gases 1 and 2 of molecular masses m 1 & m 2 respectively are closed in separate containers kept at same temperature. The ratio of speed of sound in gas 1 to that in gas 2 is given by

The pipe of length l 1 , closed at one end is kept in a chamber of gas of density ρ 1 . A second pipe open at both ends is placed in a second chamber of gas density ρ 2 , the compressibility of both gases is equal. Calculate length of the second pipe if frequency of first one in both the cases are equal.

A one meter long (both ends open) organ pipe is kept in a gas that has double the density air at STP. Assuming the speed of sound in air at STP is 300   m / sec . The frequency difference between the fundamental and second harmonic in this pipe is Hz

A speed of transverse wave on a straight wire (mass 6.0 g, length 60 cm) and area of cross-section of wire 1.0   m m 2 is 90   m / sec . If the young’s modulus of wire is 16 × 10 11 N / m 2 . The extension of wire over a natural length is mm

A wire of length l and mass per unit length 6.0 × 10 − 3   k g / m is put under tension of 540 N two consecutive frequencies that it resonates at are 420   H z and 490   H z , then l in meters is

A transverse wave travels on a taut steel wire with velocity of V when tension in it is 2.06 × 10 4 N . When the tension is changed to T. The velocity changed to V / 2 the value of T is close to × 10 3 N

The displacement Y of wave traveling in the x − direction is given by y = 10 − 4 sin 600 t − 2 x + π / 3 meters and ‘ t ‘ in seconds. The speed of the wave-motion in m / sec is

Two vibrating strings of the same material but length L and 2L have radii 2r and r respectively . They are stretched under the same tension. Both strings vibrates in their fundamental nodes. The one of length ‘L’ with frequency n 1 and other with frequency n 2 . The ratio of n 1 / n 2 is given

A wave disturbance in a medium is described by y = 0.02 cos 50 π t + π / 2 cos 10 π x where x ,   y are in meters and ‘ t ‘ in second. Which option is incorrect.

A uniform rope of length 12   m and mass 6 kg hangs vertically from a rigid support. A block of mass 2 kg is attached to free end of the rope. A transverse pulse of wavelength 0.06   m is produced at the lower end of the rope what is wavelength of pulse when it reaches the top of the rope

A whistle giving out 450   H z approaches a stationary observer at a speed of 33   m / sec . The frequency heard by the observer in H z is given velocity of sound=330 m s – 1

A copper wire is held at the two ends by rigid supports. At 30 0 C , the wire just taut, with negligible tension. Find the speed of transverse waves in this wire at 10 0 C (Young modulus of copper = 1.3 × 10 11 N / m 2 ) Co-efficient of linear expansion of copper = 1.7 × 10 − 5 / 0 c Density of copper = 9 × 10 3   k g / m 3

Speed of transverse wave on a straight wire (mass 6.0g, length 60cm and area of cross section 1.0 m m 2 ) is 90 m s – 1 . If the young’s modulus of wire in 16 × 10 11 N m − 2 the extension of wire over its natural length is.

A stationary observer receives sound from two identical tuning forks, one of which approaches and the other one recedes with the same speed (much less than the speed of sound). The observer hears 2 beats/sec. The oscillation frequency of each tuning fork is f 0 = 1400Hz and the velocity of sound in air is 350 m/s. The speed of each tuning fork is close to:

A transverse wave travels on a taut steel wire with a velocity of ν when tension in it is 2.06 x 10 4 N . When the tension is changed to T, the velocity changed to ν / 2 . The value of T is close to :

A wire length L and mass per unit length 6.0 × 10 − 3 k g m − 1 is put under tension of 540 N . Two consecutive frequencies that it resonates at are: 420 H z and 490 H z . Then L in meters is

Two identical strings X and Z made of same material have tension T X and T Z in them. If their fundamental frequencies are 450Hz and 300Hz respectively, then the ratio T X / T Z is

A wire of density 9 × 10 – 3 kg c m – 3 is stretched between two clamps 1m apart. The resulting strain in the wire is 4.9 × 10 – 4 . The lowest frequency of the transverse vibrations in the wire is (Young’s modulus of wire Y = 9 × 10 10 N m – 2 ), (to the nearest integer),

A uniform thin rope of length 12 m and mass 6 kg hangs vertically from a rigid support and a block of mass 2 kg is attached to its free end. A transverse short wave-train of wavelength 6 cm is produced at the lower end of the rope. What is the wavelength of wavetrain (in cm) when it reaches the top of the rope?

For a transverse wave travelling along a straight line, the distance between two peaks (crests) is 5 m, while the distance between one crest and one trough is 1.5 m. The possible wavelengths (in m) of the waves are :

The driver of a bus approaching a big wall notices that the frequency of his bus’s horn changes from 420Hz to 490 Hz when he hears it after it gets reflected from the wall. Find the speed of the bus if speed of the sound is 330 m s − 1

In a resonance tube experiment when the tube is filled with water up to a height of 17.0 cm from bottom, it resonates with a given tuning fork . When the level is raised the next resonance with the same tuning fork occurs at a height of 24.5 cm . If the velocity of sound in air is 330 m/s , the tuning fork frequency is :

Assume that the displacement (s) of air is proportional to the pressure difference ΔP created by a sound wave. Displacement (S) further depends on the speed of sound v , density of air ρ and the frequency f .If ΔP ~ 10Pa, v ~ 300m/s,ρ ~ 1kg/m 3 and f ~ 1000Hz then s will be of the order of ( take multiplicative constant to be 1)

A driver in a car, approaching a vertical wall notices that the frequency of his car horn, has changed from 440 Hz to 480 Hz, when it gets reflected from the wall. If the speed of sound in air is 345 m/s, then the speed of the car is:

Two waveforms, y 1 x , t = A sin k x − ω t and y 2 x , t = A sin k x + ω t + π 3 , travelling along x- axis are superposed. The position of nodes is given by k = 2 π λ ;    ω = 2 π f

The fundamental frequency of a sonometer wire of length l is f 0 . A bridge is now introduced at a distance Δ l from the centre of the wire Δ l < < l . The number of beats heard if both sides of the bridge are set into vibration in their fundamental modes are :

A transverse wave is represented by y = y 0 sin 2 π λ v t − x . For what value of λ is the maximum particle velocity equal to twice the wave velocity?

The drawing shows a frictionless incline and pulley. The two blocks are connected by a wire (mass per unit length, μ = 25  g / m ) and remain stationary. A transverse wave on the wire has a speed of 60m/s relative to it. Neglect the weight of the wire relative to the tension in the wire. If the mass m 2 be increased by 1%, the speed (in m/s) of the transverse wave relative to string will be

A boy riding on his bike is going towards east at a speed of 4 2  m / s . At a certain point, he produces a sound pulse of frequency 1650  Hz that travels in air at a speed of 334  m / s . A second boy stands on the ground 45 0 south of east from him. The frequency of the pulse as received by the second boy is (in Hz )

A long composite string is made up by joining two strings of different mass per unit length μ   and  4 μ respectively. The composite string is under the same tension. A transverse wave pulse Y = 6  mm sin 5 t + 40 x , where ‘t’ is in seconds and ‘x’ is in metres, is sent along the lighter string towards the joint. The joint is at x = 0 . The equation of the wave pulse reflected from the joint is

A train passes through a station with a constant speed. A stationary observer at the station platform measures the tone of the train whistle as 484 Hz when it approaches the station and 442 Hz when it leaves the station. If the sound velocity in air is 330m/s, then the tone of the whistle and the speed of the train are

A heavy but uniform rope of length L is suspended from a ceiling. A particle is dropped from the ceiling at the instant when the bottom end is given a transverse wave pulse. Where will the particle meet the pulse?

A tuning fork of frequency 280Hz produces 10 beats per sec when sounded with a vibrating sonometer string (in fundamental mode). When the tension in the string increases slightly, it produces 11 beats per sec. The original frequency of the vibrating sonometer string in Hz is:

A closed organ pipe of length L and an open organ pipe contain gases of densities ρ 1 and ρ 2 respectively. The compressibility of gases are equal in both the pipes. Both the pipes are vibrating in their first overtone with same frequency. The length of the open organ pipe is: (neglect the end correction)

A wire of density 9 × 10 3 kg/m 3 is stretched between two Clamps 1 m apart and is subjected to an extension of 4.9 × 10 -4 m. The lowest frequency of transverse vibration in the wire is (Y=9 × 10 10 N/m 2 )

Two pulleys of negligible mass are connected to two blocks of mass m 1 and m 2 by two strings of the same material and the same cross-sectional area as shown in Fig. The speed of a transverse wave in string AB is v 1 and that in string CD is v 2 . The ratio v 1 v 2 is

A band playing music at a frequency f is moving towards a wall at a speed u. A motorist is following the band with the same speed u. If v is the speed of sound, the beat frequency heard by the motorist is

Which of the following statements is wrong

A tuning fork makes 256 vibrations per second in air. When the velocity of sound is 330 m/s, then wavelength of the tone emitted is

Sound waves have the following frequencies that are audible to human beings

The relation between phase difference ( Δφ ) and path difference ( Δx ) is

The wavelength of ultrasonic waves in air is of the order of

The frequency of a rod is 200 Hz. If the velocity of sound in air is 340   ms − 1 , the wavelength of the sound produced is

At which temperature the speed of sound in Hydrogen will be same as that of speed of sound in Oxygen at 100 o C

A tuning fork produces waves in a medium. If the temperature of the medium changes, then which of the following will change

The wave length of light in visible part ( λ V ) and for sound ( λ S ) are related as

Which of the following is different from others

The phase difference between two points separated by 1m in a wave of frequency 120 Hz is 90 o . The wave velocity is

The echo of a gun shot is heard 8 sec after the gun is fired. How far from him is the surface that reflects the sound (velocity of sound in air = 350 m/s)

A man sets his watch by the sound of a siren placed at a distance 1 km away. If the velocity of sound is 330 m/s

Velocity of sound in air is

The frequency of a sound wave is n and its velocity is v. If the frequency is increased to 4n, the velocity of the wave will be

The temperature at which the speed of sound in air becomes double of its value at 27 o C is

The speed of a wave in a certain medium is 960 m/s. If 3600 waves pass over a certain point of the medium in 1 minute, the wavelength is

Speed of sound at constant temperature depends on

The minimum distance of reflector surface from the source for listening the echo of sound is (speed of sound = 332 m/s)

Velocity of sound in air I. Increases with temperature II. Decreases with temperature III. Increase with pressure IV. Is independent of pressure V. Is independent of temperature Choose the correct answer.

The speed of a wave in a medium is 760 m/s. If 3600 waves are passing through a point, in the medium in 2 minutes, then its wavelength is

v 1 and v 2 are the velocities of sound at the same temperature in two monoatomic gases of densities ρ 1 and ρ 2 respectively. If ρ 1 / ρ 2 = 1 4 then the ratio of velocities v 1 and v 2 will be

The frequency of a tuning fork is 384 per second and velocity of sound in air is 352 m/s. How far the sound has traversed while fork completes 36 vibration

The velocity of sound is v s in air. If the density of air is increased to 4 times, then the new velocity of sound will be

A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is 340ms -1 , the distance between the cliffs is

Velocity of sound measured in hydrogen and oxygen gas at a given temperature will be in the ratio

It takes 2.0 seconds for a sound wave to travel between two fixed points when the day temperature is 10 o C. If the temperature rise to 30 o C the sound wave travels between the same fixed parts in

If the temperature of the atmosphere is increased the following character of the sound wave is effected

An underwater sonar source operating at a frequency of 60 KHz directs its beam towards the surface. If the velocity of sound in air is 330 m/s, the wavelength and frequency of waves in air are:

Two sound waves having a phase difference of 60° have path difference of

Sound travels in rocks in the form of

Water waves are

Which of the following is the longitudinal wave

The nature of sound waves in gases is

Transverse waves can propagate in

What is the phase difference between two successive crests in the wave

Consider the following I. Waves created on the surfaces of a water pond by a vibrating sources. II. Wave created by an oscillating electric field in air. III. Sound waves travelling under water. Which of these can be polarized

Mechanical waves on the surface of a liquid are

When an aeroplane attains a speed higher than the velocity of sound in air, a loud bang is heard. This is because

The following phenomenon cannot be observed for sound waves

‘SONAR’ emits which of the following waves

The ratio of densities of nitrogen and oxygen is 14:16. The temperature at which the speed of sound in nitrogen will be same at that in oxygen at 55 o C is

A wavelength 0.60 cm is produced in air and it travels at a speed of 300 ms –1 . It will be an

Speed of sound in mercury at a certain temperature is 1450 m/s. Given the density of mercury as 13.6 × 10 3 kg / m 3 , the bulk modulus for mercury is

A point source emits sound equally in all directions in a non-absorbing medium, Two points P and Q are at distance of 2m and 3m respectively from the source. The ratio of the intensities of the waves at P and Q is

A micro-wave and an ultrasonic sound wave have the same wavelength. Their frequencies are in the ratio (approximately)

A wave has velocity u in medium P and velocity 2u in medium Q. If the wave is incident in medium P at an angle of 30° then the angle of refraction will be

An observer standing near the sea shore observes 54 waves per minute. If the wavelength of the water wave is 10m then the velocity of water wave is

The equation of a wave is y = 2 sinπ ( 0 .5 x − 200 t ) , where x and y are expressed in cm and t in sec. The wave velocity is

A travelling wave passes a point of observation. At this point, the time interval between successive crests is 0.2 seconds then

The equation of a transverse wave is given by y = 10 sinπ ( 0 .01 x − 2 t ) where x and y are in cm and t is in second. Its frequency is

At a moment in a progressive wave, the phase of a particle executing S.H.M. is π 3 . Then the phase of the particle 15 cm ahead and at the time T 2 will be, if the wavelength is 60 cm

The equation of a wave travelling on a string is y = 4 sin π 2 8 t − x 8 . If x and y are in cm, then velocity of wave is

Two waves are given by y 1 = asin ( ωt − kx ) and y 2 = acos ( ω   t − kx ) . The phase difference between the two waves is

If amplitude of waves at distance r from a point source is A, the amplitude at a distance 2r will be

A wave is reflected from a rigid support. The change in phase on reflection will be

The displacement y (in cm) produced by a simple harmonic wave is y = 10 π sin 2000 πt − πx 17 . The periodic time and maximum velocity of the particles in the medium will respectively be

The equation of a wave travelling in a string can be written as y = 3 cosπ ( 100   t − x ) . Its wavelength is

The equation of a wave motion (with t in seconds and x in metres) is given by y = 7 sin   7 πt − 0 .4 πx + π 3 . The velocity of the wave will be

The phase difference between two points separated by 0.8 m in a wave of frequency is 120 Hz is π 2 . The velocity of wave is

When a longitudinal wave propagates through a medium, the particles of the medium execute simple harmonic oscillations about their mean positions. These oscillations of a particle are characterised by an invariant

A particle on the trough of a wave at any instant will come to the mean position after a time (T = time period)

If the phase difference between the two wave is 2 π during superposition, then the resultant amplitude is

Two sources of sound A and B produces the wave of 350 Hz, they vibrate in the same phase. The particle P is vibrating under the influence of these two waves, if the amplitudes at the point P produced by the two waves is 0.3 mm and 0.4 mm, then the resultant amplitude of the point P will be when AP – BP = 25 cm and the velocity of sound is 350 m/sec

Two waves are propagating to the point P along a straight line produced by two sources A and B of simple harmonic and of equal frequency. The amplitude of every wave at P is ‘a’ and the phase of A is ahead by π 3 than that of B and the distance AP is greater than BP by 50 cm. Then the resultant amplitude at the point P will be, if the wavelength is 1 meter

Coherent sources are characterized by the same

The minimum intensity of sound is zero at a point due to two sources of nearly equal frequencies, when

The intensity ratio of two waves is 1 : 16. The ratio of their amplitudes is

Out of the given four waves (1), (2), (3) and (4) y = asin ( kx + ωt ) ……(1) y = asin ( ωt − kx ) ……(2) y = acos ( kx + ωt ) ……(3) y = acos ( ωt − kx ) ……(4) emitted by four different sources S 1 , S 2 , S 3 and S 4 respectively, interference phenomena would be observed in space under appropriate conditions when

The superposing waves are represented by the following equations : y 1 = 5 sin 2 π ( 10   t − 0 .1 x ) , y 2 = 10 sin 2 π ( 20   t − 0 .2 x ) Ratio of intensities I max I min will be

If the ratio of amplitude of wave is 2 : 1, then the ratio of maximum and minimum intensity is

The two interfering waves have intensities in the ratio 9 : 4. The ratio of intensities of maxima and minima in the interference pattern will be

Equation of motion in the same direction is given by y 1 = Asin ( ωt − kx ) , y 2 = Asin ( ωt − kx − θ ) . The amplitude of the particle will be

Two waves are represented by y 1 = asin ω   t + π 6 and y 2 = acosω   t . What will be their resultant amplitude

The displacement of the interfering light waves are y 1 = 4 sinω   t and y 2 = 3 sin ω   t + π 2 . What is the amplitude of the resultant wave

Beats are the result of

Two adjacent piano keys are struck simultaneously. The notes emitted by them have frequencies n 1 and n 2 . The number of beats heard per second is

A tuning fork of frequency 100 when sounded together with another tuning fork of unknown frequency produces 2 beats per second. On loading the tuning fork whose frequency is not known and sounded together with a tuning fork of frequency 100 produces one beat, then the frequency of the other tuning fork is

If two tuning forks A and B are sounded together, they produce 4 beats per second. A is then slightly loaded with wax, they produce 2 beats when sounded again. The frequency of A is 256. The frequency of B will be

The frequencies of two sound sources are 256 Hz and 260 Hz. At t = 0, the intensity of sound is maximum. Then the phase difference at the time t = 1/16 sec will be

When a tuning fork of frequency 341 is sounded with another tuning fork, six beats per second are heard. When the second tuning fork is loaded with wax and sounded with the first tuning fork, the number of beats is two per second. The natural frequency of the second tuning fork is

Two tuning forks of frequencies 256 and 258 vibrations/sec are sounded together, then time interval between consecutive maxima heard by the observer is

If the wave equation y = 0 .08 sin 2 π λ ( 200 t − x ) then the velocity of the wave will be

Two waves of same frequency and intensity superimpose with each other in opposite phases, then after superposition the

The amplitude of a wave represented by displacement equation y = 1 a sinωt ± 1 b cosωt will be

A tuning fork gives 5 beats with another tuning fork of frequency 100 Hz. When the first tuning fork is loaded with wax, then the number of beats remains unchanged, then what will be the frequency of the first tuning fork

Tuning fork F 1 has a frequency of 256 Hz and it is observed to produce 6 beats/second with another tuning fork F 2 . When F 2 is loaded with wax, it still produces 6 beats/second with F 1 . The frequency of F 2 before loading was

The beats are produced by two sound sources of same amplitude and of nearly equal frequencies. The maximum intensity of beats will be …… that of one source

A tuning fork of frequency 480 Hz produces 10 beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string if a slight increase in tension produces lesser beats per second than before

When two sound waves are superimposed, beats are produced when they have

A source of sound gives five beats per second when sounded with another source of frequency 100 s -1 . The second harmonic of the source together with a source of frequency 205 s -1 gives five beats per second. What is the frequency of the source

A tuning fork whose frequency as given by manufacturer is 512 Hz is being tested with an accurate oscillator. It is found that the fork produces a beat of 2 Hz when oscillator reads 514 Hz but produces a beat of 6 Hz when oscillator reads 510 Hz. The actual frequency of fork is

Two tuning forks have frequencies 380 and 384 Hz respectively. When they are sounded together, they produce 4 beats. After hearing the maximum sound, how long will it take to hear the minimum sound

Two tuning forks A and B give 4 beats per second. The frequency of A is 256 Hz. On loading B slightly, we get 5 beats in 2seconds. The frequency of B after loading is

A tuning fork A of frequency 200 Hz is sounded with fork B, the number of beats per second is 5. By putting some wax on A, the number of beats increases to 8. The frequency of fork B is

Two tuning forks A and B vibrating simultaneously produce 5 beats. Frequency of B is 512. It is seen that if one arm of A is filed, then the number of beats increases. Frequency of A will be

Two tuning forks, A and B, give 4 beats per second when sounded together. The frequency of A is 320 Hz. When some wax is added to B and it is sounded with A, 4 beats per second are again heard. The frequency of B is

When a tuning fork A of unknown frequency is sounded with another tuning fork B of frequency 256 Hz, then 3 beats per second are observed. After that A is loaded with wax and sounded, the again 3 beats per second are observed. The frequency of the tuning fork A is

Beats are produced by two waves given by y 1 = asin 2000   πt and y 2 = asin 2008   πt . The number of beats heard per second is

Beats are produced by two waves y 1 = a sin 1000 πt , y 2 = a sin 998 πt The number of beats heard/sec is

It is possible to hear beats from the two vibrating sources of frequency

Two sound sources when sounded simultaneously produce four beats in 0.25 second. the difference in their frequencies must be

The couple of tuning forks produces 2 beats in the time interval of 0.4 seconds. So the beat frequency is

The wavelengths of two waves are 50 and 51 cm respectively. If the temperature of the room is 20 o C, then what will be the number of beats produced per second by these waves, when the speed of sound at 0 o C is 332 m/sec

An unknown frequency x produces 8 beats per seconds with a frequency of 250 Hz and 12 beats with 270 Hz source, then x is

A tuning fork gives 4 beats with 50 cm length of a sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is (in Hz)

Two sound waves of wavelengths 5m and 6m formed 30 beats in 3 seconds. The velocity of sound is

A tuning fork of known frequency 256 Hz makes 5 beats per second with the vibrating string of a piano. The beat frequency decreases to 2 beats per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was

Two strings X and Y of a sitar produce a beat frequency 4 Hz. When the tension of the string Y is slightly increased the beat frequency is found to be 2 Hz. If the frequency of X is 300 Hz, then the original frequency of Y was

When a tuning fork vibrates, the waves produced by the fork are

The frequency of tuning forks A and B are respectively 3% more and 2% less than the frequency of tuning fork C. When A and B are simultaneously excited, 5 beats per second are produced. Then the frequency of the tuning fork ‘A’ (in Hz) is

When temperature increases, the frequency of a tuning fork

A tuning fork vibrates with 2 beats in 0.04 second. The frequency of the fork is

Two vibrating tuning forks produce progressive waves given by Y 1 = 4 sin 500 πt and Y 2 = 2 sin 506 πt . Number of beats produced per minute is

When a tuning fork produces sound waves in air, which one of the following is same in the material of tuning fork as well as in air

The disc of a siren containing 60 holes rotates at a constant speed of 360 rpm. The emitted sound is in unison with a tuning fork of frequency

Stationary waves are formed when

The phase difference between the two particles situated on both the sides of a node is

Which of the property makes difference between progressive and stationary waves

For the stationary wave y = 4 sin   πx 15 cos ( 96   πt ) , the distance between a node and the next antinode is (in m)

The equation of stationary wave along a stretched string is given by y = 5 sin πx 3 cos 40 πt , where x and y are in cm and t in second. The separation between two adjacent nodes is

The equation of a stationary wave is y = 0 .8 cos   πx 20 sin 200   πt , where x is in cm and t is in sec. The separation between consecutive nodes will be

In a stationary wave, all particles are

The equation φ   ( x ,   t ) = j   sin   2 π λ v   t cos   2 π λ x represents

In stationary waves, antinodes are the points where there is

The equation y = 0 .15 sin 5 x cos 300 t , describes a stationary wave. The wavelength of the stationary wave is

Stationary waves of frequency 300 Hz are formed in a medium in which the velocity of sound is 1200 metre/sec. The distance between a node and the neighbouring antinode is

In stationary waves, distance between a node and its nearest antinode is 20 cm. The phase difference between two particles having a separation of 60 cm will be

A standing wave having 3 nodes and 2 antinodes is formed between two atoms having a distance 1.21 Å between them. The wavelength of the standing wave is

“Stationary waves” are so called because in them

The stationary wave produced on a string is represented by the equation y = 5 cos ( πx / 3 ) sin 40 πt . Where x and y are in cm and t is in seconds. The distance between consecutive nodes is

Two waves are approaching each other with a velocity of 20 m/s and frequency n. The distance between two consecutive nodes is

Which two of the given transverse waves will give stationary waves when get superimposed z 1 = acos ( kx − ω   t ) …..(A) z 2 = acos ( kx + ω   t ) …..(B) z 3 = acos ( ky − ω   t ) …..(C)

Two waves are approaching each other with a velocity of 20 m/s and frequency n. The distance between two consecutive nodes is

Two sinusoidal waves with same wavelengths and amplitudes travel in opposite directions along a string with a speed 10 ms –1 . If the minimum time interval between two instants when the string is flat is 0.5 s, the wavelength of the waves is

In a stationary wave all the particles

Stationary waves

Energy is not carried by which of the following waves

y = acos ( kx + ωt ) superimposes on another wave giving a stationary wave having node at x = 0. What is the equation of the other wave

A wave of frequency 100 Hz is sent along a string towards a fixed end. When this wave travels back after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speed of incident (and reflected) wave are

Equation of a stationary wave is y = 10 sin πx 4 cos 20 πt . Distance between two consecutive nodes is

In stationary waves

When a stationary wave is formed then its frequency is

The following equations represent progressive transverse waves Z 1 = Acos ( ω   t − kx ) , Z 2 = Acos ( ω   t + kx ) , Z 3 = Acos ( ω   t + ky ) and Z 4 = Acos ( 2 ω   t − 2 ky ) . A stationary wave will be formed by superposing

Consider the three waves z 1 , z 2 and z 3 as z 1 = Asin ( kx − ω   t ) , z 2 = Asin ( kx + ω   t ) and z 3 = Asin ( ky − ω   t ) . Which of the following represents a standing wave

Two travelling waves y 1 = Asin [ k ( x − c   t ) ] and y 2 = Asin [ k ( x + c   t ) ] are superimposed on string. The distance between adjacent nodes is

A string vibrates according to the equation y = 5 sin   2 πx 3    cos   20   πt , where x and y are in cm and t in sec. The distance between two adjacent nodes is

A string fixed at both the ends is vibrating in two segments. The wavelength of the corresponding wave is

Which of the following is the example of transverse wave

A 1 cm long string vibrates with fundamental frequency of 256 Hz. If the length is reduced to 1 4 cm keeping the tension unaltered, the new fundamental frequency will be (in Hz)

The velocity of waves in a string fixed at both ends is 2 m/s. The string forms standing waves with nodes 5.0 cm apart. The frequency of vibration of the string in Hz is

Standing waves are produced in a 10 m long stretched string. If the string vibrates in 5 segments and the wave velocity is 20 m/s, the frequency is

A stretched string of 1m length and mass 5 × 10 − 4 kg is having tension of 20N. If it is plucked at 25cm from one end then it will vibrate with frequency

Two similar sonometer wires given fundamental frequencies of 500Hz. These have same tensions. By what amount the tension be increased in one wire so that the two wires produce 5 beats/sec

A string is producing transverse vibration whose equation is y = 0.021   sin ( x + 30 t ) , Where x and y are in meters and t is in seconds. If the linear density of the string is 1 .3 × 10 − 4 kg/m, then the tension in the string in N will be

Frequency of a sonometer wire is n. Now its tension is increased 4 times and its length is doubled then new frequency will be

If the tension of sonometer’s wire increases four times then the fundamental frequency of the wire will increase by

Four wires of identical length, diameters and of the same material are stretched on a sonometre wire. If the ratio of their tensions is 1 : 4 : 9 : 16 then the ratio of their fundamental frequencies are

If you set up the ninth harmonic on a string fixed at both ends, its frequency compared to the seventh harmonic

A tuning fork vibrating with a sonometer having 20 cm wire produces 5 beats per second. The beat frequency does not change if the length of the wire is changed to 21 cm. the frequency of the tuning fork (in Hertz) must be

The tension in a piano wire is 10N. What should be the tension in the wire to produce a note of double the frequency

A string of 7 m length has a mass of 0.035 kg. If tension in the string is 60.5 N, then speed of a wave on the string is

A string on a musical instrument is 50 cm long and its fundamental frequency is 270 Hz. If the desired frequency of 1000 Hz is to be produced, the required length of the string is

A second harmonic has to be generated in a string of length l stretched between two rigid supports. The point where the string has to be plucked and touched are

The tension of a stretched string is increased by 69%. In order to keep its frequency of vibration constant, its length must be increased by

A sonometer wire resonates with a given tuning fork forming standing waves with five antinodes between the two bridges when a mass of 9 kg is suspended from the wire. When this mass is replaced by a mass M, the wire resonates with the same tuning fork forming three antinodes for the same positions of the bridges. The value of M is

Length of a string tied to two rigid supports is 40 cm. Maximum length (wavelength in cm) of a stationary wave produced on it is

The length of a sonometer wire tuned to a frequency of 250 Hz is 0.60 metre. The frequency of tuning fork with which the vibrating wire will be in tune when the length is made 0.40 metre is

Transverse waves of same frequency are generated in two steel wires A and B. The diameter of A is twice of B and the tension in A is half that in B. The ratio of velocities of wave in A and B is

A string in musical instrument is 50 cm long and its fundamental frequency is 800 Hz. If a frequency of 1000 Hz is to be produced, then required length of string is

Two wires are in unison. If the tension in one of the wires is increased by 2%, 5 beats are produced per second. The initial frequency of each wire is

Two uniform strings A and B made of steel are made to vibrate under the same tension. if the first overtone of A is equal to the second overtone of B and if the radius of A is twice that of B, the ratio of the lengths of the strings is

Two wires are fixed in a sonometer. Their tensions are in the ratio 8 : 1. The lengths are in the ratio 36 : 35. The diameters are in the ratio 4 : 1. Densities of the materials are in the ratio 1 : 2. If the lower frequency in the setting is 360 Hz. the beat frequency when the two wires are sounded together is

If the length of a stretched string is shortened by 40% and the tension is increased by 44%, then the ratio of the final and initial fundamental frequencies is

A tuning fork of frequency 392 Hz, resonates with 50 cm length of a string under tension (T). If length of the string is decreased by 2%, keeping the tension constant, the number of beats heard when the string and the tuning fork made to vibrate simultaneously is

The frequency of transverse vibrations in a stretched string is 200 Hz. If the tension is increased four times and the length is reduced to one-fourth the original value, the frequency of vibration will be

Two perfectly identical wires are in unison. When the tension in one wire is increased by 1%, then on sounding them together 3 beats are heard in 2 sec. The initial frequency of each wire is :

Two wires are producing fundamental notes of the same frequency. Change in which of the following factors of one wire will not produce beats between them

Three similar wires of frequency n 1 , n 2 and n 3 are joined to make one wire. Its frequency will be

Calculate the frequency of the second harmonic formed on a string of length 0.5 m and mass 2 × 10 –4 kg when stretched with a tension of 20 N

The fundamental frequency of a string stretched with a weight of 4 kg is 256 Hz. The weight required to produce its octave is

If the tension and diameter of a sonometer wire of fundamental frequency n are doubled and density is halved then its fundamental frequency will become

Two vibrating strings of the same material but lengths L and 2L have radii 2r and r respectively. They are stretched under the same tension. Both the strings vibrate in their fundamental modes, the one of length L with frequency n 1 and the other with frequency n 2 . The ratio n 1 /n 2 is given by

In a sonometer wire, the tension is maintained by suspending a 50.7 kg mass from the free end of the wire. The suspended mass has a volume of 0.0075 m 3 . The fundamental frequency of the wire is 260 Hz. If the suspended mass is completely submerged in water, the fundamental frequency will become (take g = 10 ms –2 )

A string is rigidly tied at two ends and its equation of vibration is given by y = cos 2 π t sin 2 πx . Then minimum length of string is

A string of length 2 m is fixed at both ends. If this string vibrates in its fourth normal mode with a frequency of 500 Hz then the waves would travel on its with a velocity of

Fundamental frequency of sonometer wire is n. If the length, tension and diameter of wire are tripled, the new fundamental frequency is

A tube closed at one end and containing air is excited. It produces the fundamental note of frequency 512 Hz. If the same tube is open at both the ends the fundamental frequency that can be produced is

In an experiment with sonometer a tuning fork of frequency 256 Hz resonates with a length of 25 cm and another tuning fork resonates with a length of 16 cm. Tension of the string remaining constant the frequency of the second tuning fork is

A closed pipe and an open pipe have their first overtones identical in frequency. Their lengths are in the ratio

An empty vessel is partially filled with water, then the frequency of vibration of air column in the vessel

An air column in a pipe, which is closed at one end, will be in resonance with a vibrating body of frequency 166 Hz, if the length of the air column is

If the length of a closed organ pipe is 1m and velocity of sound is 330 m/s, then the frequency for the second note is

The fundamental note produced by a closed organ pipe is of frequency f. The fundamental note produced by an open organ pipe of same length will be of frequency

An organ pipe P 1 closed at one end vibrating in its first overtone and another pipe P 2 open at both ends vibrating in its third overtone are in resonance with a given tuning fork. The ratio of lengths of P 1 and P 2 is

If the length of a closed organ pipe is 1.5 m and velocity of sound is 330 m/s, then the frequency for the second note is

A cylindrical tube, open at both ends, has a fundamental frequency f 0 in air. The tube is dipped vertically into water such that half of its length is inside water. The fundamental frequency of the air column now is

A resonance air column of length 20 cm resonates with a tuning fork of frequency 250 Hz. The speed of sound in air is

A pipe 30 cm long is open at both ends. Which harmonic mode of the pipe is resonantly excited by a 1.1 kHz source ? (Take speed of sound in air = 330 ms –1 )

Two closed organ pipes, when sounded simultaneously gave 4 beats per sec. If longer pipe has a length of 1m. Then length of shorter pipe will be, (v = 300 m/s)

The harmonics which are present in a pipe open at one end are

Two open organ pipes give 4 beats/sec when sounded together in their fundamental nodes. If the length of the pipe are 100 cm and 102.5 cm respectively, then the velocity of sound is :

A closed organ pipe and an open organ pipe are tuned to the same fundamental frequency. What is the ratio of lengths

If v is the speed of sound in air then the shortest length of the closed pipe which resonates to a frequency n

Two open organ pipes of length 25 cm and 25.5 cm produce 10 beat/sec. The velocity of sound will be

Fundamental frequency of pipe is 100 Hz and other two frequencies are 300 Hz and 500 Hz then

If the temperature increases, then what happens to the frequency of the sound produced by the organ pipe

Standing stationary waves can be obtained in an air column even if the interfering waves are

If in an experiment for determination of velocity of sound by resonance tube method using a tuning fork of 512 Hz, first resonance was observed at 30.7 cm and second was obtained at 63.2 cm, then maximum possible error in velocity of sound is (consider actual speed of sound in air is 332 m/s)

Stationary waves are set up in air column. Velocity of sound in air is 330 m/s and frequency is 165 Hz. Then distance between the nodes is

A student determines the velocity of sound with the help of a closed organ pipe. If the observed length for fundamental frequency is 24.7 m, the length for third harmonic will be

What is the base frequency if a pipe gives notes of frequencies 425, 255 and 595 and decide whether it is closed at one end or open at both ends

An open pipe of length 33 cm resonates with frequency of 1000 Hz. If the speed of sound is 330 m/s, then this frequency is

In a resonance tube the first resonance with a tuning fork occurs at 16 cm and second at 49 cm. If the velocity of sound is 330 m/s, the frequency of tuning fork is (in Hz)

In open organ pipe, if fundamental frequency is n then the other frequencies are

An open tube is in resonance with string (frequency of vibration of tube is n 0 ). If tube is dipped in water so that 75% of length of tube is inside water, then the ratio of the frequency of tube to string now will be

A whistle sends out 256 waves in a second. If the whistle approaches the observer with velocity 1/3 of the velocity of sound in air, the number of waves per second the observer will receive

An observer moves towards a stationary source of sound of frequency n. The apparent frequency heard by him is 2n. If the velocity of sound in air is 332 m/sec, then the velocity of the observer is

An observer is moving towards the stationary source of sound, then

The source producing sound and an observer both are moving along the direction of propagation of sound waves. If the respective velocities of sound, source and an observer are v, v s and v 0 , then the apparent frequency heard by the observer will be (n = frequency of sound)

A person feels 2.5% difference of frequency of a motor-car horn. If the motor-car is moving to the person and the velocity of sound is 320 m/sec, then the velocity of car will be

The frequency of a whistle of an engine is 600 cycles/sec is moving with the speed of 30 m/sec towards an observer. The apparent frequency will be (velocity of sound = 330 m/s)

An observer while going on scooter hears sound of two sirens of same frequencies from two opposite directions. If he travels along the direction of one of the siren, then he

A source of sound is travelling towards a stationary observer. The frequency of sound heard by the observer is of three times the original frequency. The velocity of sound is v m/sec. The speed of source will be

A source and listener are both moving towards each other with speed v/10, where v is the speed of sound. If the frequency of the note emitted by the source is f, the frequency heard by the listener would be nearly

Suppose that the speed of sound in air at a given temperature is 400 m/sec. An engine blows a whistle at 1200 Hz frequency. It is approaching an observer at the speed of 100 m/sec. What is the apparent frequency as heard by the observer

The Doppler’s effect is applicable for

A source of sound S of frequency 500 Hz situated between a stationary observer O and a wall W, moves towards the wall with a speed of 2 m/s. If the velocity of sound is 332 m/s, then the number of beats per second heard by the observer is (approximately)

A source of sound of frequency n is moving towards a stationary observer with a speed S. If the speed of sound in air is V and the frequency heard by the observer is n 1 , the value of n 1 / n is

A vehicle with a horn of frequency n is moving with a velocity of 30 m/s in a direction perpendicular to the straight line joining the observer and the vehicle. The observer perceives the sound to have a frequency n + n 1 when he is at the shortest distance between them. Then (if the sound velocity in air is 300 m/s)

An observer standing at station observes frequency 219 Hz when a train approaches and 184 Hz when train goes away from him. If velocity of sound in air is 340 m/s, then velocity of train and actual frequency of whistle will be

At what speed should a source of sound move so that stationary observer finds the apparent frequency equal to half of the original frequency

A source of sound is travelling with a velocity 40 km/hour towards observer and emits sound of frequency 2000 Hz. If velocity of sound is 1220 km/hour, then what is the apparent frequency heard by an observer

A source of sound and listener are approaching each other with a speed of 40 m/s. The apparent frequency of note produced by the source is 400 cps. Then, its true frequency (in cps) is (velocity of sound in air = 360 m/s)

A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is f 1 . If the train’s speed is reduced to 17 m/s, the frequency registered is f 2 . If the speed of sound is 340 m/s then the ratio f 1 / f 2 is

A whistle of frequency 500 Hz tied to the end of a string of length 1.2 m revolves at 400 rev/min. A listener standing some distance away in the plane of rotation of whistle hears frequencies in the range (speed of sound = 340 m/s)

A source of sound of frequency 90 vibrations/ sec is approaching a stationary observer with a speed equal to 1/10 the speed of sound. What will be the frequency heard by the observer

If source and observer both are relatively at rest and if speed of sound is increased then frequency heard by observer will

A man sitting in a moving train hears the whistle of the engine. The frequency of the whistle is 600 Hz

A siren placed at a railway platform is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is

A whistle revolves in a circle with an angular speed of 20 rad/sec using a string of length 50 cm. If the frequency of sound from the whistle is 385 Hz, then what is the minimum frequency heard by an observer, which is far away from the centre in the same plane ? (v = 340 m/s)

A source emits a sound of frequency of 400 Hz, but the listener hears it to be 390 Hz. Then

Two trains are moving towards each other at speeds of 20 m/s and 15 m/s relative to the ground. The first train sounds a whistle of frequency 600 Hz. the frequency of the whistle heard by a passenger in the second train before the train meets is (the speed of sound in air is 340 m/s)

Doppler effect is applicable for

A police car horn emits a sound at a frequency 240 Hz when the car is at rest. If the speed of the sound is 330 m/s, the frequency heard by an observer who is approaching the car at a speed of 11 m/s, is :

A source and an observer approach each other with same velocity 50 m/s. If the apparent frequency is 435 sec –1 , then the real frequency is

When an engine passes near to a stationary observer then its apparent frequencies occurs in the ratio 5/3. If the velocity of engine is

A bus is moving with a velocity of 5 m/s towards a huge wall. the driver sounds a horn of frequency 165 Hz. If the speed of sound in air is 355 m/s, the number of beats heard per second by a passenger on the bus will be

The apparent frequency of a note, when a listener moves towards a stationary source, with velocity of 40 m/s is 200 Hz. When he moves away from the same source with the same speed, the apparent frequency of the same note is 160 Hz. The velocity of sound in air is (in m/s)

The walls of the halls built for music concerts should

A spherical source of power 4 W and frequency 800 Hz is emitting sound waves. The intensity of waves at a distance 200 m is

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency

If the pressure amplitude in a sound wave is tripled, then the intensity of sound is increased by a factor of

If the amplitude of sound is doubled and the frequency reduced to one-fourth, the intensity of sound at the same point will be

Decibel is unit of

Quality of a musical note depends on

A is singing a note and at the same time B is singing a note with exactly one-eighth the frequency of the note of A. The energies of two sounds are equal, the amplitude of the note of B is

A man x can hear only upto 10 kHz and another man y upto 20 kHz. A note of frequency 500 Hz is produced before them from a stretched string. Then

The loudness and pitch of a sound depends on

A musical scale is constructed by providing intermediate frequencies between a note and its octave which

In a harmonium the intermediate notes between a note and its octave form

If separation between screen and source is increased by 2% what would be the effect on the intensity

In an orchestra, the musical sounds of different instruments are distinguished from one another by which of the following characteristics

The musical interval between two tones of frequencies 320 Hz and 240 Hz is

In the musical octave ‘Sa’, ‘Re’, ‘Ga’

Of the following the one which emits sound of higher pitch is

The intensity level due to two waves of the same frequency in a given medium are 1 bel and 5 bel. Then the ratio of amplitudes is

It is possible to recognise a person by hearing his voice even if he is hidden behind a wall. This is due to the fact that his voice

Learned Indian classical vocalists do not like the accompaniment of a harmonium because

Intensity level 200 cm from a source of sound is 80 dB. If there is no loss of acoustic power in air and intensity of threshold hearing is 10 − 12 Wm − 2 then, what is the intensity level at a distance of 4000 cm from source

Quality depends on

Two identical flutes produce fundamental notes of frequency 300 Hz at 27 0 C. If the temperature of air in one flute is increased to 31 0 C, the number of the beats heard per second will be

A train has just complicated a U-curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is 30 m/sec is

A closed organ pipe of length L and an open organ pipe contain gases of densities ρ 1 and ρ 2 respectively. The compressibility of gases are equal in both the pipes. Both the pipes are vibrating in their first overtone with same frequency. The length of the open organ pipe is

A string of length 0.4 m and mass 10 − 2   kg is tightly clamped at its ends. The tension in the string is 1.6 N. Identical wave pulses are produced at one end at equal intervals of time Δt . The minimum value of Δt which allows constructive interference between successive pulses is

If the velocity of sound in air is 336 m/s. The maximum length of a closed pipe that would produce a just audible sound will be

A source of sound placed at the open end of a resonance column sends an acoustic wave of pressure amplitude ρ 0 inside the tube. If the atmospheric pressure is ρ A , then the ratio of maximum and minimum pressure at the closed end of the tube will be

Two closed pipe produce 10 beats per second when emitting their fundamental nodes. If their length are in ratio of 25 : 26. Then their fundamental frequency in Hz, are

Find the fundamental frequency of a closed pipe, if the length of the air column is 42 m. (speed of sound in air = 332 m/sec)

An open pipe resonates with a tuning fork of frequency 500 Hz. it is observed that two successive nodes are formed at distances 16 and 46 cm from the open end. The speed of sound in air in the pipe is

The stationary wave y = 2 a sin kx cos ωt in a closed organ pipe is the result of the superposition of y = a sin ( ω   t − kx ) and

On producing the waves of frequency 1000 Hz in a Kundt’s tube, the total distance between 6 successive nodes is 85 cm. Speed of sound in the gas filled in the tube is

What is minimum length of a tube, open at both ends, that resonates with tuning fork of frequency 350 Hz ? [velocity of sound in air = 350 m/s]

Tube A has both ends open while tube B has one end closed, otherwise they are identical. The ratio of fundamental frequency of tube A and B is

The difference between the apparent frequency of a source of sound as perceived by an observer during its approach and recession is 2% of the natural frequency of the source. If the velocity of sound in air is 300 m/sec, the velocity of the source is (It is given that velocity of source << velocity of sound)The difference between the apparent frequency of a source of sound as perceived by an observer during its approach and recession is 2% of the natural frequency of the source. If the velocity of sound in air is 300 m/sec, the velocity of the source is (It is given that velocity of source << velocity of sound)

In one metre long open pipe what is the harmonic of resonance obtained with a tuning fork of frequency 480 Hz

An organ pipe open at one end is vibrating in first overtone and is in resonance with another pipe open at both ends and vibrating in third harmonic. The ratio of length of two pipes is

Two whistles A and B produces notes of frequencies 660 Hz and 596 Hz respectively. There is a listener at the mid-point of the line joining them. Now the whistle B and the listener start moving with speed 30 m/s away from the whistle A. If speed of sound be 330 m/s, how many beats will be heard by the listener

A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observes any beats

Oxygen is 16 times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of speed of sound in the mixture to that in hydrogen is

The equation of displacement of two waves are given as y 1 = 10 sin 3 πt + π 3 ; y 2 = 5 ( sin 3 πt + 3 cos 3 πt ) . Then what is the ratio of their amplitudes

Consider ten identical sources of sound all giving the same frequency but having phase angles which are random. If the average intensity of each source is I 0 , the average of resultant intensity I due to all these ten sources will be

The equation y = Acos 2 2 πnt − 2 π x λ represents a wave with

16 tuning forks are arranged in the order of increasing frequencies. Any two successive forks give 8 beats per sec when sounded together. If the frequency of the last fork is twice the first, then the frequency of the first fork is (in Hz)

25 tuning forks are arranged in series in the order of decreasing frequency. Any two successive forks produce 3 beats/sec. If the frequency of the first tuning fork is the octave of the last fork, then the frequency of the 21 st fork is

Two identical wires have the same fundamental frequency of 400 Hz. when kept under the same tension. If the tension in one wire is increased by 2% the number of beats produced will be

The frequency of a stretched uniform wire under tension is in resonance with the fundamental frequency of a closed tube. If the tension in the wire is increased by 8 N, it is in resonance with the first overtone of the closed tube. The initial tension in the wire is

A wire of density 9 × 10 3 kg /m 3 is stretched between two clamps 1 m apart and is subjected to an extension of 4.9 × 10 -4 m. The lowest frequency of transverse vibration in the wire is (Y = 9 × 10 10 N / m 2 )

A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg weight between two rigid supports 1 metre apart. The wire passes at its middle point between the poles of a permanent magnet, and it vibrates in resonance when carrying an alternating current of frequency n. The frequency n of the alternating source is

A man is watching two trains, one leaving and the other coming in with equal speeds of 4 m/sec. If they sound their whistles, each of frequency 240 Hz, the number of beats heard by the man (velocity of sound in air = 320 m/sec) will be equal to

An organ pipe is closed at one end has fundamental frequency of 1500 Hz. The maximum number of overtones generated by this pipe which a normal person can hear is :

Three waves of equal frequency having amplitudes 10 μ m, 4 μ m and 7 μ m arrive at a given point with successive phase difference of π 2 . The amplitude of the resulting wave in μ m is given by

A person speaking normally produces a sound intensity of 40 dB at a distance of 1 m. If the threshold intensity for reasonable audibility is 20 dB, the maximum distance at which he can be heard clearly is

There are three sources of sound of equal intensity with frequencies 400, 401 and 402 vib/sec. The number of beats heard per second is

The diagram below shows the propagation of a wave. Which points are in same phase

Fig. below shows the wave y = Asin ( ωt − kx ) at any instant travelling in the +ve x-direction. What is the slope of the curve at B

Figure here shows an incident pulse P reflected from a rigid support. Which one of A, B, C, D represents the reflected pulse correctly

A sound source emits sound waves in a uniform medium. If energy density is E and maximum speed of the particles of the medium is v max . The plot between E and v max is best represented by

The correct graph between the frequency n and square root of density ( ρ ) of a wire, keeping its length, radius and tension constant, is

If the speed of the wave shown in the figure is 330 m/s in the given medium, then the equation of the wave propagating in the positive x-direction will be (all quantities are in M.K.S. units)

Two pulses travel in mutually opposite directions in a string with a speed of 2.5 cm/s as shown in the figure. Initially the pulses are 10cm apart. What will be the state of the string after two seconds

The diagram below shows an instantaneous position of a string as a transverse progressive wave travels along it from left to right Which one of the following correctly shows the direction of the velocity of the points 1, 2 and 3 on the string

The displacement-time graphs for two sound waves A and B are shown in the figure, then the ratio of their intensities I A / I B is equal to

A wave motion has the function y = a 0 sin ( ω   t − kx ) . The graph in figure shows how the displacement y at a fixed point varies with time t. Which one of the labelled points shows a displacement equal to that at the position x = π 2 k at time t = 0

A wave is travelling along a string. At an instant, shape of the string is as shown in fig. At this instant, point A is moving upwards. Which of the following statements is/are correct

In the experiment for the determination of the speed of sound in air using the resonance column method, the length of the air column that resonates in the fundamental mode, with a tuning fork is 0 . 1 m . When this length is changed to 0 . 35 m , the same tuning fork resonates with the first overtone. Calculate the end correction.

Corresponding to given observation calculate speed of sound. Frequency of tuning fork = 340 Hz Resonance Length from the water level (in cm) During falling During rising First 23.9 24.1 Second 73.9 74.1

A student is performing the experiment of resonance column. The diameter of the column tube is 4 cm . The frequency of the tuning fork is 512 Hz . The air temperature is 38 ° C in which the speed of sound is 336 m / s . The zero of the meter scale coincides with the top end of the resonance, column tube. When the first resonance occurs, the reading of the water level in the column is

If a tuning fork of frequency ( 340 ± 1 % ) is used in the resonance tube method and the first and second resonance lengths are 20 . 0 cm and 74 . 0 cm respectively. Find the maximum possible percentage error in speed of sound.

A boy seeing a lighting starts counting seconds, until he hears thunder. He then claims to have found an approximate but simple rule that if count of second is divided by an integer, the result directly gives the distance of lighting source in km. What is the integer. Take sound velocity as 330 m/s.

AB is a cylinder of length 1 m fitted with a thin flexible diaphragm C at the middle and two other thin flexible diaphragm at ends A and B which do not allow outside air to mix with H 2 and O 2 gas as shown. Find the minimum frequency of a tuning fork which can establish sustained stationary waves in cylinder with diaphragm C as a node. Given that velocity of sound in H 2 is 1100 m/s and in O 2 , is 300 m/s.

A progressive wave is given by y = 3 sin ⁡ 2 π [ ( t / 0 .04 ) − ( x / 0 .01 ) ] where x, y are in cm and t in s. The frequency of wave and maximum acceleration will be:

A resonance occurs with a tuning fork and an air column of size 12 cm. The next higher resonance occurs with an air column of 38 cm. What is the frequency of the tuning fork? Assume that the speed of sound is 312 m/s.

The transverse displacement of a string clamped at its both ends is given by y ( x , t ) = 0 .06 sin ⁡ 2 π 3 x cos ⁡ ( 120 πt ) where x and y are in m and t in s. The length of the string is 1.5 m and its mass is 3 × 10 − 2 kg . The tension in the string is

A tube of certain diameter and of length 48 cm is open at both ends. Its fundamental frequency of resonance is found to be 320 Hz. The velocity of sound in air is 320 m/s. One end of the tube is now closed, considering the effect of end correction, calculate the lowest frequency of resonance for the tube (in Hz).

A wire having a linear density of 5 g/m is stretched between two rigid supports with a tension of 450 N. It is observed that the wire resonates at a frequency of 420 Hz. The next highest frequency at which the same wire resonates is 490 Hz. Find the length of the wire.

The intensity of sound from a point source is 1 .0 × 10 − 8 W / m 2 at a distance of 5.0 m from the source. What will be the intensity at a distance of 25 m from the source? (in × 10 − 10 W / m 2 )

Two wires of ratio of lengths 1:2 and tensions in the ratio 3:1 have the ratio of their fundamental frequencies having ratio 2:1. Find the ratio of their masses.

A source of sonic oscillations with frequency n = 1700 Hz and a receiver are located on the same normal to a wall. Both the source and receiver are stationary, and the wall recedes from the source with velocity u = 6.0 cm/s. Find the beat frequency (in Hz) registered by the receiver. The velocity of sound is equal to v = 340 m/s.

A source of sound having natural frequency f 0 = 1800 Hz is moving uniformly along a line separated from a stationary listener by a distance l = 250 m. The velocity of source is n = 0.80 times the velocity of sound. Find the frequency of sound (in Hz) received by the listener at the moment when the source gets closest to him.

Two tuning forks A and B produce 10 beats per second when sounded together. On slightly loading fork A with a little wax, it was observed that 15 beats are heard per second. If the frequency of fork B is 480 Hz. what is the frequency of fork A (in Hz) before it was loaded?

A sonometer wire resonates with a given tuning fork forming standing waves with five antinodes between the two bridges when a mass of 9 kg is suspended from the wire. When this mass is replaced by a mass M, the wire resonates with the same tuning fork forming three antinodes for the same positions of the bridges. The value of M is

A particle on a stretched string supporting a travelling wave, takes 5.0 ms to move from its mean position to the extreme position. The distance between two consecutive particles, which are at their mean positions, is 3.0 cm. Find the wave speed (in m/s).