PhysicsPhysics QuestionsElectromagnetic Waves Questions for CBSE Class 12th

Electromagnetic Waves Questions for CBSE Class 12th

A linearly polarized electromagnetic wave given as E = E o cos ( k z − w t ) i ^ is incident normally on a perfectly reflecting infinite wall at z = a . Assuming that the material of the wall is optically inactive, the reflected wave will be given as

An electromagnetic wave of frequency 3.0 M H z passes from Vacuum into a non-magnetic medium with permittivity ∈ = 25 ∈ 0 , where ∈ 0 is the free space permittivity. The change in wavelength is

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    A parallel plate capacitor made of circular plate each of radius 10 cm has a capacitance 200 pF. The capacitor is connected to a 200 V supply with an angular frequency of 200 rad/s. What is the peak value of displacement current?

    The amplitude of the electric field in a parallel beam of plane electromagnetic waves of intensity 53.1 W m − 2 is (permittivity of free space= 8.85 × 10 − 12 C 2 / N m 2 )

    The magnetic field in a plane electromagnetic wave is given by B y = 2 × 10 − 7 sin ( 0.5 × 10 3 x + 1.5 × 10 11 t ) . This electromagnetic wave is

    A parallel plate capacitor has plate area of 1   c m 2 and plate separation 0.5 mm. When the capacitor is being charged, the electric field in the space between the plates is increasing at the rate of 10 10 V / m – s . Then the displacement current at that instant is

    A plane electromagnetic wave is propagating along the direction i ^ + j ^ 2 , with its polarization along the direction k ^ . The correct form of the magnetic field of the wave would be (here B 0 is an appropriate constant)

    A plane electromagnetic wave E z = 100 cos 6 × 10 8 t + 4 x V / m propagates in a medium of dielectric constant. The refractive index of the medium is

    Find the value of magnetic field between plates of capacitor at a distance 1 m from centre, where electric field varies by 10 10 V/m per second.

    In an electromagnetic wave, the electric and magnetizing fields are 100 V/m and 0.265 A/m. The average rate of flow of energy is

    The equation of a plane polarised electromagnetic wave is given as E y = E 0 sin(at – bx)

    An electromagnetic wave travels along + ve Zaxis. Which of the following pairs of space and time varying fields would generate such a wave ?

    A radiation of energy ‘E’ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C = Velocity of light )

    Inside a parallel plate capacitor the electric field E varies with time as t 2 . The variation of induced magnetic field with time is given by :

    A plane electromagnetic wave of frequency 20 MHz travels in free space along the x-direction. At a particular point in a space and time the magnetic field vector is B = 3 × 10 − 8 T   k ∧ . Calculate electric field vector ( E ) at this point

    An electromagnetic wave with pointing vector 12   w a t t   m − 2 is absorbed by a surface of area is 24 m 2 . The force on the surface is × 10 − 8 N

    The peak value of electric field produced by the radiation coming from a 100   w a t t bulb at a distance of 3 m is ( assume that the efficiency of the bulb is 2.5% and it is a point source)

    If the magnetic field of a plane electromagnetic wave is given by B = 5 × 10 − 6 sin [ 0.6 × 10 2 x + 0.5 × 10 10 t ] then the speed of the wave is

    In an electromagnetic wave the electric and magnetizing fields are 100 V / m and 0.265 A / m . The maximum rate of energy flow is

    An electromagnetic wave in vacuum has the electric and magnetic fields E and B , which are always perpendicular to each other. The direction of polarization is given by X and that of wave propagation by K . Then

    An electromagnetic wave of intensity I falls on a surface kept in vacuum and exerts radiation pressure P on it. Choose wrong option from the following

    The time varying magnetic and electric fields

    The rms value of the electric field of the light coming from the sun is 720 N/C. The average total energy density of the electromagnetic wave is

    The Maxwell’s equation ∮ B . dl = μ 0 i + ε 0 ϕ E dt is a statement of

    The electric field for an electromagnetic wave in free space is E = i 30 cos kz – 5 x 10 8 t , where magnitude of E is in V/m. The magnitude of wave vector, k is (velocity of EM wave in free space = 3×10 8 m/s)

    The wave impedance of free space is

    The frequencies of X-rays, γ -rays and ultraviolet rays are respectively a, b and c. Then

    It μ r be the relative permeability and k r the relative dielectric constant of a medium, its refractive index is given by

    In an electromagnetic wave, electric field E and magnetic field B are

    The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

    In an electromagnetic wave in free space the root mean square value of the electric field is E rms = 6 Vm – 1 . The peak value of the magnetic field is

    The magnetic field in a plane electromagnetic wave is given by B = ( 200 μ T ) sin ( 4.0 x 10 15 s − 1 ) ( t − x / c ) . Find the average energy density corresponding to the electric field.

    Amplitude of electric field in a parallel beam of light of intensity 8    w / m 2 is

    The amplitude of the electric field in a parallel beam of plane electromagnetic waves of intensity 106.2 W m − 2 is (permittivity of free space= 8.85 × 10 − 12 C 2 / N m 2 )

    Light with an energy flux of 18   W / c m 2 falls on a non reflecting surface at normal incidence. If the surface has an area of 20   c m 2 . The average force exerted on the surae during a 30 minute time spam is

    A parallel plate capacitor of plate separation 8.85 mm is connected in an electric circuit having source voltage 400V. What is the value of the displacement current for 10 – 6 sec , if the plate area is 60 c m 2 ?

    In a travelling plane electromagnetic wave the maximum magnetic fields is 2.52 × 10 − 4 T . The intensity of the wave is (Assume , μ 0 = 1.26 × 10 − 6 H / m )

    A plane electromagnetic wave propagating in a non magnetic dielectric medium is given by E = E 0 sin [ 2 × 10 − 7 x − 50 t ] , where ‘ x ‘ is in meter and ‘ t ‘ is in second. If the relative permeability of the medium μ r = 1 then the dielectric constant of the medium is

    If the magnetic field of a plane electromagnetic wave is given by B = 1 × 10 − 6 sin [ 0.4 × 10 2 x + 0.3 × 10 10 t ] T . Then the speed of the wave is

    A beam of light travelling along x-axis is described by the electric field E Y = ( 300 V m − 1 ) sin ω ( t − x C ) . Calculate the maximum magnetic force on a charge q = 4 e , moving along y-axis with a speed of 2 × 10 7 m / s is (where e = 1.6 × 10 − 19 C )

    Sea water at frequency V = 2 × 10 8 H z has permittivity ∈ ≈ 60 ∈ 0 , permeability, μ ≈ μ 0 and resistivity ρ = 0.50 Ω − m .Imagine a parallel plate capacitor with plate gap of 1m, immersed in sea water and driven by an alternating Voltage of 200 V then the maximum conduction current density is V Ω m 2

    How would you establish an instantaneous current 4A in the space between the two parallel plates of 2 μ F capacitor?

    In a plane electromagnetic wave, the electric field oscillates with amplitude 20 V m − 1 , then the energy density of magnetic field is (in J / m 3 )

    A capacitor made of two circular plates each of radius 12 cm and separated by 5mm. The capacitor is being charged by an external source. The charging current is constant and equal to 0.15A. The magnetic field between the plates at a point 15 cm from the axis is

    The average energy flux of sunlight is 1.0 k W m − 2 . This energy of radiation is falling normally on the metal plate surface of area 10 c m 2 which completely absorbs the energy. The force exerted on the plate if it is exposed to sunlight for 10 minutes is

    A plane electromagnetic wave propagating in a non-magnetic dielectric medium is given by E = E 0 sin [ 4 × 10 − 7 x − 50 t ] .Where ‘ x ‘ is in meter and ‘ t ‘ is in second. If the relative permeability of the medium, μ r = 1 then the dielectric constant of the medium is

    If the intensity of the incident radio wave of 1   w a t t   m − 2 is reflected by the surface the pressure exerted on the surface is × 10 − 9 N / m 2

    The refractive index and the permeability of a medium are respectively 1.5 and 10 × 10 − 7 H m − 1 . The relative permittivity of the medium is nearly

    A linearly polarized electromagnetic wave given as E = E 0 cos ( k z − w t ) i ^ is incident normally on a perfectly reflecting infinite wall at z=a. Assuming that the material of the wall is optically inactive, the reflected wave will be given as

    A plane electro magnetic wave is propagating in free space. If average energy density at a point is u then amplitude of electric field is

    A plane electro magnetic wave is propagating in free space. Then select the correct option

    Displacement current is

    Time varying electrical field is produced along with time varying magnetic field, by

    A parallel plate condenser has conducting plates of radius 12 cm separated by a distance of 5 mm. It is charged with a constant charging current of 0.16 A, the rate at which the potential difference between the plates change is

    Light with energy flux 36 W/cm 2 is incident on a well polished metal square plate of side 2 cm. The force experienced by it is

    The relative permeability of glass is 3/8 and the dielectric constant of glass is 8. The refractive index of glass is

    In an apparatus the electric field was found to oscillate with an amplitude of 18 Vm -1 . The rms value of the oscillating magnetic field is

    A parallel plate condenser of capacity 10 μ F is connected to an A.C. supply voltage e = 4 sin(100 π t). The maximum displacement current.

    A long straight wire of resistance R, radius ‘a’ and length ‘L’ carries a constant current “I”. The poynting vector for the wire is

    For a transparent medium relative permeability and permittivity, μ r and ∈ r are 1.0 and 1.44 respectively. The velocity of light in this medium would be,

    Plane electromagnetic waves of intensity S are incident normally on a flat surface. Only a fraction f of the incident energy is absorbed. What is the radiation pressure?

    A flood light is covered with a filter that transmits red light. The electric field of the emerging beam is represented by a sinusoidal plane wave E x = 36 sin(1.20×10 7 z – 3.6×10 15 t)V/m. The average intensity of the beam will be

    A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10 m from the lamp will be

    Light with an energy flux of 20 W/cm 2 falls on a non-reflecting surface at normal incidence. If the surface has an area of 30 cm 2 the total momentum delivered (for complete absorption) during 30 minutes is

    A wave is propagating in a medium of dielectric constant 2 and relative permeability 50. The wave impedance is

    A wave is propagating in a medium of dielectric constant 2 and relative permeability 50. The wave impedance is

    Find amplitude of electric field in parallel beam of light of intensity 6 10 π  W / m 2 . and take 1 4 π ε 0 = 9 × 10 9 Nm 2 / C 2

    In an electro magnetic wave

    A condenser has two conducting plates of radius 10 cm separated by a distance of 5 mm. It is charged with a constant current of 0.15 A. The magnetic field at a point 2 cm from the axis in the gap is

    Maxwell’s equation ∫ E . dl = – dϕ m dt is a statement of

    An electromagnetic wave travelling in the x-direction has frequency of 3×10 14 Hz and electric field amplitude of 27 Vm –1 . From the options given below, which one describes the magnetic field for this wave ?

    Radiations of intensity 0 .5 W / m 2 are striking a metal plate. The pressure on the plate is

    In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption?

    The wavelength of infrared rays is of the order of

    A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10 m from the lamp will be

    Which of the following waves has the maximum wavelength?

    A plane electromagnetic wave of intensity of 10 W / m 2 strikes a small mirror of area 20 cm 2 , held perpendicular to the approaching wave. The radiation force on the mirror will be

    In an electromagnetic wave, the electric field oscillates sinusoidally with amplitude 48 Vm − 1 . The RMS value of oscillating magnetic field will be

    If λ v , λ x and λ m represent the wavelengths of visible light, X-rays and microwaves, respectively, then

    The velocity of electromagnetic radiation in a medium of permittivity ε 0 and permeability μ 0 is given by

    The electric and magnetic field of an electromagnetic wave is

    The frequency of e.m. wave which is best suited to observe a particle of radius 3 × 10 − 4 cm , is of the order of

    The frequency 1057 MHz of radiation arising from two close energy levels in hydrogen belong to

    The wave associated with 2.7 K belong to

    Electromagnetic waves travel in a medium which has relative permeability 1.3 and relative permittivity 2.14. Then the speed of the electromagnetic wave in the medium will be

    Displacement current exists between the plates of a capacitor only when the charge on the capacitor changes with time.

    Ratio of intensities of two waves are given by 4 : 1′ Then the ratio of the amplitudes of the two waves is

    Which of the following pairs of space and time varying E and B fields would generate a plane electromagnetic wave travel ling in the Z-direction ?

    Electromagnetic waves in nature are

    The relation between electric field E and magnetic field H in an electromagnetic wave/is

    The distance up to which T.V, signals can be received depends upon

    In an electromagnetic wave, the electric and magnetising fields are 100 V m – 1 and 0 . 265 A m – 1 . The maximum energy flow is

    A plane electromagnetic ware travelling in a non-magnetic medium is given by E = 9 × 10 8 NC − 1 sin ⁡ 9 × 10 8 rads − 1 t − 6 m − 1 x where x is in metre and t is in second. The dielectric constant of the medium is

    The electric field of a plane electromagnetic wave varies with time of amplitude 2 Vm – 1 propagating along z-axis. The average energy density of the magnetic field is (in J m – 3 )

    An EM wave is propagating in a medium with a velocity v = v i ^ . The instantaneous oscillating electric field of this EM wave is along +y axis. Then the direction of oscillating magnetic field of the EM wave will be along

    An electromagnetic wave is travelling to the east. At one instant at a given point its E points straight up. What is the direction of B ?

    A parallel plate capacitor of capacitance 20 μF is being charged by a voltage source whose potential is changing at the rate of 3 V/s. The conduction current through the connecting wires, and the displacement current through the plates of the capacitor, would be, respectively

    The energy of the em waves is of the order of 15keV. To which part of the spectrum does it belong?

    A plane electromagnetic wave is given by E= 100 cos (6x 10 8 t + 4x) V/m propagating in a dielectric medium. The refractive index of the medium is

    43 Electromagnetic wave is propagating in x direction. Magnetic field in space is given by B = 2 × 10 – 8 k ^ T . What will be the value and direction of electric field?

    A plane strip suspended by string on which monochromatic light is incedent on strip have power P. Find deflection of string from vertical if strip is perfect black body

    An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity ∈ = 4.0. Then

    Regarding a monochromatic plane electromagnetic wave travelling in free space the true statement is

    The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic waves is : ( c= speed of electromagnetic waves)

    Monochromatic light of wavelength 3000 A o is incident on a surface are 4 c m 2 . If intensity of light is 150 m w / m 2 , then rate at which protons strike the target is

    For a transparent medium, relative permeability and permittivity, μ r and ∈ r are 1.0 and 1.44 respectively. The velocity of light in this medium would be,

    Electric field of electromagnetic wave is given by E = 50    sin t − x c N / C . Then intensity of waves is

    Back e.m.f. in a d.c. motor is maximum when

    A ring of radius R has uniformly distributed charge. It spins about its axis with an angular velocity ω . P is a point on its axis at a distance x, from its centre. The velocity of light in vaccum is c. Then the ratio of magnetic field to the electric field at P is equal to

    In an electromagnetic wave instantaneous value of magnetic field is 2 μ T . Then instantaneous value of electric field at that instant is

    The rms value of electric field of the Light coming from the sun is 720 N/C. The average total energy density of the electromagnetic wave is

    An electromagnetic wave of frequency f = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity ε r = 4.0 and relative permeability μ r = 1 . 0 Then

    A beam of light travelling along x-axis described by the magnetic field, B z = 5 × 10 − 10 sin w ( t − X c ) T . Calculate the maximum magnetic force on alpha particle, moving along y-axis with a speed of 3 × 10 7 m / s . Charge on electron is 1.6 × 10 − 19 C .

    A parallel plate capacitor of capacity 100 p F is connected to 230 V of AC supply of 300   r a d / s frequency. The value of displacement current is

    A condenser has two conducting plates of radius 10   c m separated by a distance of 5 m m . It is charged with a constant current of 0.15 A . The magnetic field at a point 2 c m from the axis in the gap is

    A lamp emits monochromatic light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of electrical power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 10 m from the lamp will be

    The electric field of a plane electromagnetic wave varies with time of amplitude 2 V m − 1 propagating along z-axis. The average energy density of the magnetic field is( in J m − 3 )

    The sun delivers 10 3 W / m 2 of electromagnetic flux to the earth’s surface. The total power that is incident on a roof of dimensions 8 m × 20 m is 1.6 × 10 5 W , then the radiation force on the roof will be

    In an electromagnetic wave in vacuum, the electric and magnetic fields are 40 π V / m and 0.4 × 10 − 7 T . The poynting vector is

    The oscillating electric field of an electromagnetic wave is given by E Y = 30 sin [ 2 × 10 11 t + 300 π x ] V m − 1 . Then , the value of wavelength of the electromagnetic wave is

    If the intensity of the incident radio wave is 3   w a t t   m − 2 is reflected by the surface, the pressure exerted on the surface is × 10 − 8 N / m 2

    A parallel plate of capacitor made of circular plates each of radius 20.0   c m has a capacitance 100 p F . The capacitor is connected to a source of 220 V and angular frequency of 200   r a d / s , the rms value of the displacement current is μ A

    The refractive index and the permeability of a medium are respectively 4 3 and 4 × 10 − 7 H m − 1 . The relative permittivity of the medium is

    In a plane electromagnetic wave the electric field oscillates sinusoidally at a frequency 3 × 10 10 H z and amplitude 50 V/m. What is the amplitude of the oscillating magnetic fields?

    The magnetic field in a plane electromagnetic wave is given by B y = 2 × 10 − 7   sin ( 0.1 × 10 3 x + 1.1 × 10 11 t ) T . Write an expression for the electric field

    If the wave front of electromagnetic wave travelling in vacuum is given by r = i ^ + j ^ + k ^ , find the angle made by the direction of propagation of electromagnetic wave with z-axis?

    The charge on a parallel plate capacitor varies Q = Q o sin 2 π f t . The plates are very large and close together ( area of plates is A and separation is d) Neglecting the edge effects, the displacement current through the capacitor is

    A parallel plate condenser of capacity 10 μ F is connected to an AC supply Voltage e = 4 sin ( 100 π t ) . The maximum displacement current is

    Light with an energy flux of 25 × 10 4 W / m 2 falls on a perfectly reflecting surface area is 15   c m 2 , the average force exerted on the surface is

    An electromagnetic wave of frequency 3 × 10 6 H z ( 3.0 M H z ) passes from vacuum into a non magnetic medium with permittivity, ∈ = 16 ∈ 0 , where ∈ 0 is the free space permittivity. The change in wavelength is

    In a travelling plane electromagnetic wave the maximum magnetic field is 1.26 × 10 − 4 T . The intensity of the wave is (Assume μ 0 = 1.26 × 10 − 6 H / m )

    A magnetic field in a plane electromagnetic wave is given by B Y = 3 × 10 − 7 sin [ 1.5 x + 5 × 10 8 t ] T . What is the wavelength of electromagnetic wave?

    A beam of light travelling along x-axis is described by the electric field E Y = ( 600 V m − 1 ) sin ω ( t − x c ) , then the maximum magnetic force on a charge q = 2 e moving along y-axis with a speed of 3 × 10 7 m / s is (where e = 1.6 × 10 − 19 C )

    A parallel plate capacitor made of circular plates each of radius 10.0   c m has a capacitance 200 p F . The capacitor is connected to a 200 V   a   c supply with an angular frequency of 100 r a d / s . The rms value of the conduction current is μ A

    An electromagnetic wave with poynting vector 6   w a t t   m − 2 is absorbed by a surface of area 12 m 2 . The force on the surface is × 10 − 8 N

    Sea water at frequency V = 4 × 10 8 H z has permittivity ∈ ≈ 80 ∈ 0 , permeability μ ≈ μ 0 and resistivity ρ = 0.25 Ω − m . Imagine a parallel plate capacitor immersed in sea water and driven by an alternating Voltage of 400 V then the maximum conduction current density is V o l t / o h m   m 2 ( distance between the plates , d = 1   m )

    The energy contained in a small volume through which an electromagnetic wave is passing oscillates with

    The kinetic energy of a photon of frequency ϑ , rest mass m o , having mass m while moving with velocity v is

    Consider the following types of electromagnetic radiations ; radio waves, infrared, visible light. Which of the following statements are correct? i) Only radio waves can be used to transmit audio information ii) Only infrared radiation is emitted by very hot object. iii) Only visible light can be detected by humans

    The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

    An electromagnetic wave travelling along z-axis is given as E = E o cos ( k z − w t ) ( – j ^ ) . Choose the wrong option from the following

    Comparing the masses of the two photons, of red light and violet light

    A plane electromagnetic wave propagating along x-direction can have the following pairs of E ¯   and  B ¯

    A plane electromagnetic wave E Z = 100 c o s 6 ×   10 8 t + 4 x v o l t / m propagates in a medium of refractive index

    Radiation pressure on any surface

    A linearly polarized electromagnetic wave given as E = E 0 i ^ cos k z − ω t is incident normally on a perfectly reflacting wall z = a . Assuming that the material of the optically inactive, the reflected wave will be given as

    Electromagnetic waves with wave length are given. Arrange these wavelengths in decreasing order of magnitude a) λ 1 are used to treat muscular strain b) λ 2 are used by a FM radio station for broadcasting c) λ 3 are used to detect fracture in bones d) λ 4 are absorbed by the ozone layer of the atmosphere

    A photon of light enters a block of glass after travelling through vacuum. The energy of the photon on entering the glass block

    A flood light will be covered with filter that transmits red light. The electric field of the emerging beam is represented by a sinusoidal plane wave E X = 38.8 sin 1.2 × 10 7 z − 3.6 × 10 15 t v m The average intensity of beam in w a t t m 2 will be

    The energy stored in a 90 cm length of a laser beam operating at 10 mW is × 10 − 12 J

    One requires 11 e V of energy to dissociate a carbon monoxide molecules into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in

    Electromagnetic waves of frequency 1.2 × 10 15 H z enter into water and subsequently into glass from Vacuum. Which of the following graphs correctly represent the variation of frequency ‘ f ‘ with medium? ( given that indices of refraction for water and glass are 4 3 and 3 2 respectively)

    An electromagnetic wave radiates outwards from a dipole antenna with E 0 as the amplitude of its electric field vector. The electric field E 0 which transports significant energy from the source falls off as

    Choose the correct sequence of radiation sources in increasing order of the wavelength of electromagnetic waves produced by them

    During the propagation of electromagnetic waves in a medium

    The electric field associated with a propagating electromagnetic wave is described by the equation E = E 0 sin 4 π × 10 6 x − 1.2 π × 10 15 t volt/ meter , where x is in meter and t is second. The wavelength of the wave in the unit of 10 − 7 m is

    The speed of electromagnetic wave in the unit of 10 8 m / s , in a medium of dielectric constant 2.25 and relative permeability 4 is

    A condenser has two conducting plates of radius 10   c m separated by a distance of 5   m m . It is charged with a constant current of 0.15 A . The magnetic field at a point 1  c m from the axis in the gap is × 10 − 8 T

    The magnetic field in the plane electromagnetic wave is given by B Z = 2 x 10 – 7 sin ( 0 . 5 x 10 3 x + 1 . 5 x 10 11 t ) .The expression for electric field will be

    The Sun delivers about 900 W/ m 2 of energy to the Earth’s surface at midday time at a place. The force exerted by the radiation on a shiny roof top of dimensions 10 m × 5 m is (assume that the roof top is a perfect reflector)

    In an electromagnetic wave, the amplitude of electric field is 1V/m. The frequency of wave is 5 x 10 14 H z . The wave is propagating along z-axis.The average energy density of electric field, in Joule/m3, will be

    If a wave can be polarised, it must be

    Instantaneous displacement current of 1.0 A in the space between the parallel plates of a 1 μ F capacitor can be established by changing potential difference of:

    The electric field of an electromagnetic wave in a medium is given by Ex= 0, , Ez = 0, and E y = 2 . 5 V m – 1 cos 2 π x 10 6 r a d s – 1 t – π x 10 – 2 m – 1 x , The wave is

    The rms value of electric field of the light coming from sun in 720 N/C. The average energy density of em wave is

    If the magnetic field in a plane electromagnetic wave is given by B = 3 × 10 − 8 sin 1.6 × 10 3 x + 48 × 10 10 t j ^ T ; then what will be the expression for the electric field?

    The Electric field of a plane electromagnetic wave is given by E = E 0 i ^ + j ^ 2 cos K z + ω t . At t=0, a positively charged particle is at the point x , y , z = 0 , 0 , π K .If its instantaneous velocity at (t=0) is v 0 k ^ , the force acting on it due to the wave is:

    The dimension of B 2 2 μ 0 , where B is magnetic field and μ 0 is the magnetic permeability of vacuum, is:

    A plane electromagnetic wave is propagating through free space. If amplitude of electric field is 50 v/m, the intensity of the wave is

    A plane electromagnetic wave of frequency 25 GHz is propagating in vacuum along the z-direction. At a particular point in space and time, the magnetic field is given by B =5×10 -8 j ^  T . The corresponding electric field E is (speed of light c = 3 x 10 8 m s − 1 )

    A plane electromagnetic wave is propagating in a transparent medium having relative permeability 1.6 and relative permittivity 1.8, Then refractive index of the medium is

    The electric fields of two plane electromagnetic plane waves in vacuum are given by E 1 = E 0 j ^ cos   ω t − k x and E 2 = E 0 k ^    cos   ω t − k y . At t = 0 , a particle of charge q is at origin with a velocity v = 0.8   c j ^ (c is the speed of light in vacuum). The instantaneous force experienced by the particle is :

    A plane electromagnetic wave, has frequency of 2.0 × 10 10   H z and its energy density is 1.02 × 10 − 8 J / m 3 in vacuum. The amplitude of the magnetic field of the wave is close to 1 4 π ε 0 = 9 × 10 9 N m 2 C 2 a n d    s p e e d    o f    l i g h t    = 3 × 10 8   m s − 1 :

    A laser beam can be focussed on an area equal to the square of its wavelength. A laser source radiates energy at the rate of 1mW and its wavelength is 632.8nm. The intensity of focussed beam will be

    In a plane electromagnetic wave, the directions of electric filed and magnetic field are represented by k ^ and 2 i ^ − 2 j ^ , respectively. What is the unit vector along direction of propagation of the wave.

    Consider the following two statements regarding a linearly polarized, plane electromagnetic wave: (A) The electric field and the magnetic field have equal average values. (B) The electric energy and the magnetic energy have equal average values.

    The magnetic field of a plane electromagnetic wave is B = 3 × 10 − 8 sin 200 π y + c t i ^ T where c = 3 × 10 8 m s − 1 is the speed of light. The corresponding electric field is :

    The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is E = E 0 j ^ cos ω t − k x . The magnetic field B , at the moment t = 0 is

    Choose the correct option relating wavelengths of different parts of electromagnetic wave spectrum :

    The electric field of a plane electromagnetic wave is given by E = E 0 x ^ + y ^ sin k z − ω t . Its magnetic field will be given by

    An Electron is constrained to move along the y-axis with a speed of 0.1 c( c is the speed of light ) in the presence of electronic wave , whose electric field E =30  sin(1.5×10 7 t-5×10 -2 x)V/m. The maximum magnetic force experienced by the electron will be : ( Given C = 3×10 8  ms -1 and electron charge =1.6×10 -19 C )

    The correct match between the entries in column I and column II are: I II Radiation Wavelength a) Microwave i) 100 m b) Gamma rays ii) 10 – 15 m c) A.M. radio iii) 10 – 10 m waves d) X-rays iv) 10 – 3 m

    The most penetrating radiation out of the following is

    If λ 1    and    λ 2 are the wave length of characteristic X-rays and gamma rays respectively, then the relation between them is

    A plane electro magnetic wave is propagating through space consider unit area perpendicular to the direction of propagation. If E  ​and  B are instantaneous electric and magnetic field components then instantaneous rate of energy flow through the unit area is given by

    An electro magnetic wave is propagating through space, then at a point the ratio of energy density produced by electric component to the total energy density is

    A plane electro magnetic wave is propagating in vacuum such that average energy density at a point is 5   μ J / m 3 . Then intensity of the wave is

    A plane electro magnetic wave is propagating through space. It at any instant of time E = E 0 sin ω t − k x j ^ and B = − B 0 sin ω t − k x k ^ , the wave is carrying energy along

    An electromagnetic wave is propagating in a medium. If intensity of wave is 1200 W m 2 and average energy density is 6   μ J / m 3 , find the refractive index of the medium.

    The electro magnetic wave, represented by E = 0.04 sin 2 × 10 4 t − 10 − 4 x V / m is propagating in a transparent medium. If μ and ∈ be the permeability and permittivity of the medium then the value of ‘ μ ∈ ‘ is

    In an electromagnetic wave, the magnetic field is given by B = 2 × 10 – 7 sin 0 . 5 × 10 3 x + 1 . 5 × 10 11 t t e s l a . The intensity of electromagnetic wave is about (in W m 2 )

    The rms values of the electric field of the light coming from sun is 1000 N/C. The average energy density of the EM wave is × 10 –6 J/m 3

    An electromagnetic wave going through vacuum is described by E = E o sin k x − ω t and B = B o sin k x − ω t . Which of the following equations is true?

    A plane electromagnetic wave of frequency 25 MHz travels in free space along the x-direction. At a particular point in space and time, electric field is E = 6.3 j ^  V / m . Strength of the magnetic field at this point

    The dimension of (1/2) ε 0 E 2 ε 0 : permittivity of free space; E: electric field) is

    The electric field of a plane electromagnetic wave varies with time of amplitude propagating along z-axis. The average energy density of the magnetic field is (in J m-(c)

    The electric field of a plane electro magnetic wave, propagating along z-axis is given by E = 2 sin 8 π x 10 14 t – 8 π 3 x 10 6 z v / m Then average intensity of the wave is

    White light forms a continuous spectrum of minimum wavelength 3800 A 0 corresponding to violet light and maximum wavelength 7800 A 0 corresponding to red light. Find the minimum and maximum frequencies of white light. (c = 3 ×10 8 m/s).

    Maxwell’s equation ∮ B . ds = 0 is a statement of

    A Parallel plate condenser of capacity 100 pF is connected to 230 V of AC supply of 300 rad / sec frequency. The rms value of displacement current

    A parallel plate capacitor of plate separation 2 mm is connected in an electric circuit having source voltage 400 V. If the plate area is 60 cm 2 , then the value of displacement current for 10 -6 sec will be

    An AC rms voltage of 2 V having a frequency of 50 kHz is applied to a condenser of capacity of 10 μF. The maximum value of the magnetic field between the plates of the condenser, if the radius of plate is 10 cm is

    A condenser is charged using a constant current. The ratio of the magnetic fields at a distance of R/2 and R from the axis is (R is the radius of plate)

    The magnetic field, between the plates of radius 12 cm separated by distance of 4 mm of a parallel plate capacitor of capacitance 100 pF, along the axis of plates having conduction current of 0.15 A is

    A wave is propagating in a medium of dielectric constant 2 and relative permeability 50. The wave impedance is

    An electromagnetic wave of frequency 3 MHz passes from Vacuum into a dielectric medium with relative permittivity ∈ r = 4.0 Then

    A plane e.m. wave of frequency 40 MHz travels along X – axis. At same point at same instant, the electric field E has maximum value of 750 N/C in Y – direction. The magnitude and direction of magnetic field is

    A Plane electromagnetic wave of frequency 25 MHz travels in free space along the x-direction. At a particular point in space and time E ¯ = 6 . 3 j ˆ . The magnetic field B at this point is

    The amplitude of the sinusoidally oscillating electric field of a plane wave is 60 V/m. Then the amplitude of the magnetic field is

    For plane electromagnetic waves propagating in the z direction, which one of the following combination gives the correct possible direction for E and B field respectively?

    Light with energy flux of 24 Wm –2 is incident on a well polished disc of radius 3.5 cm for one hour. The momentum transferred to the disc is

    Light with energy flux of 18 W/cm 2 falls on a non reflecting surface of area 20 cm 2 at normal incidence. The momentum delivered in 30 minutes is

    The maximum electric field of a plane electromagnetic wave is 88 V/m. The average energy density is

    The rms value of the electric field of a plane electromagnetic wave is 314 V/m. The average energy density of electric field and the average energy density are

    The intensity of TV broad cast station of E = 800 Sin (10 9 t – k x) V/m is ……… and the wave length in meter is …………..

    A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is (C=velocity of light)

    The energy of the electromagnetic waves is of the order of 15 keV. To which part of the spectrum does it belong ?

    In an electromagnetic wave in free space the root mean square value of the electric field is E rms = 6 V/m. The peak value of the magnetic field is

    The incident intensity of an a horizontal surface at sea level from sun is about 1 kW/m 2 . Assuming that 50% of this intensity is reflected and 50% is absorbed, then the radiation pressure on this horizontal surface

    The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is

    An electromagnetic wave in vacuum has the electric and magnetic fields E and B , which are always perpendicular to each other. The direction of polarization is given by X and that of wave propagation by k . Then :

    The electric field of an electromagnetic wave in free space is given by E = 10 cos 10 7 t + kx j ^ V / m , where t and x are in seconds and metres respectively. It can be inferred that 1) the wavelength λ is 188.4 m 2) the wave number k is 0.33 rad/m. 3) the wave amplitude is 10 V/m. 4) the wave is propagating along + x direction. Which one of the following pairs of statements is correct ?

    The electric field associated with an EM wave in vacuum is given by E = 40 cos kz – 6 x 10 8 t i ^ , where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is

    Estimate how many photons of yellow light ( λ = 575 nm) must be absorbed by 1.0 cm 3 of human skin to raise the skin temperature by 1.0 °C. Assume that the photon energy is absorbed by 1.0 cm 3 of tissue. As rough estimates of the tissue’s density and specific heat, use the values for water.

    A plane electromagnetic wave of frequency 25MHz travels in free space along the x-direction . At a particular point in the space and time, if the intensity of electric field E = 6.3 j ^  V / m , the magnetic induction B at this point is

    The electric field of plane electromagnetic wave of amplitude 2V/m varies with time, propagating along z-axis. The average energy density of magnetic field in J / m 3 is equal to x × 10 − 12  J / m 3 . Then ‘x’ value is equal to ( ∈ 0 = 8.854 × 10 − 12  F / m )

    Monica wanted to take photographs of a monument. But since the surrounding is filled with smoke, she is not able to take good photos. Which one of the following electromagnetic waves can be used in this situation to help Monica?

    The radiation force experienced by body exposed to radiation of intensity I, assuming surface of body to be perfectly absorbing is:

    If E and B are the electric and magnetic field vectors of E.M. waves then the direction of propagation of E.M. waves is along the direction of

    In an electromagnetic wave, the average energy density associated with magnetic field is

    Which of the following has zero average value in a plane electromagnetic wave?

    Light wave is travelling along y-direction. If the corresponding E vector at any time is along the x-axis, the direction of B vector at that time is along

    Light is an electromagnetic wave. ls speed in vacuum is given by the expression (All symbols have their usual meaning)

    In an apparatus, the electric field was found to oscillate with an amplitude of 18 V/m. The magnitude of the oscillating magnetic field will be

    According to Maxwell’s hypothesis, a changing electric field gives rise to

    An electromagnetic wave going through vacuum is described by E = E 0 sin ( kx − ωt ) ; B = B 0 sin ( kx − ωt ) Which of the following equations is true?

    If c is the speed of electromagnetic waves in vacuum, its speed v in a medium of dielectric constant K and relative permeability μ r is (c is the speed of light)

    A long straight wire of resistance R, radius a and length l carries a constant current I. The poynting vector for the wire will be

    In an electromagnetic wave, the amplitude of electric field is 1 V/m and the frequency of wave is 5 × 10 14 Hz . The wave is propagating along z-axis. The average energy density of electric field, in J/m 3 , will be

    A laser beam can be focused on an area equal to the square of its wavelength. A He-Ne laser radiates energy at the rate of 1 mW and its wavelength is 632.8 nm. The intensity of focused beam will be

    An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity ε r = 4 .0 . Then

    In an e.m. wave propagating in vacuum , the electric field oscillates sinusoidally at a frequency of 2 .5 × 10 10 Hz and amplitude 480 V/m. The amplitude of oscillating magnetic field will be

    Dimensions of 1 / μ 0 ε 0 is (All symbols have their usual meaning)

    Which radiation in sunlight causes heating effect?

    Which of the following radiations has the least wavelength?

    The percentage power of X-ray increases with the increases in its

    Which of the following wavelength falls in X-rays region?

    The range of wavelength of the visible light is

    The ozone layer absorbs

    Electromagnetic radiation of highest frequency is

    Radio waves and visible light in vacuum have

    The wavelength of ultraviolet rays is of the order of

    Which of the following rays has the maximum frequency?

    What is ozone hole?

    The average energy density of electromagnetic wave given by E = ( 50 N / C ) sin ( ωt − kx ) will be nearly

    A circular ring of radius r is placed in a homogeneous magnetic field perpendicular to the plane of the ring. The field B changes with time according to the equation B = Kt, where K is a constant and r is the time. The electric field in the ring is

    In a region of free space, the electric field at some instant of time is E = ( 80 i ^ + 32 j ^ − 64 k ^ ) V m and the magnetic field is B = ( 0 .2 i ^ + 0 .08 j ^ − 0 .29 k ^ ) μT . The pointing vector for these fields is

    Statement 1: The eye is most sensitive for the light of frequency 5.36 × 10 14 Hz . Statement 2: The frequency of light is directly proportional to wavelength of light.

    which of the following shows greenhouse effect?

    Pick out the longest wavelength from the following types of radiations.

    A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance 4.0 m from the source is

    The pressure exerted by an electromagnetic wave of intensity I (watts/m 2 ) on a non-reflecting surface is [c is the velocity of light]

    If ε 0 and μ 0 represent the permittivity and permeability of vacuum and ε and μ represent the permittivity and permeability of medium, the refractive index of the medium is given by

    The average value of electric energy density in an electromagnetic wave is (E 0 is peak value)

    What is the cause of “Green house effect”?

    Choose the correct option which contains the law for which Maxwell introduced the concept of displacement current to resolve the conceptual contradiction.

    The wavelength of ultraviolet rays is of the order of :

    In a place e.m. wave, the electric field oscillates sinusoidally at a frequency of 2.5 × 10 10 Hz and amplitude 480 Vm − 1 . The amplitude of oscillating magnetic field will be :

    Light of different colours propagates through air

    The number of wavelengths in the visible spectrum

    Visible range of wavelength in cm is

    The shortest wavelength is for

    Which has the longest wavelength ?

    The speed of electromagnetic wave in vacuum is given by

    A parallel plate capacitor consists of two circular r plates each of radius z cm, separated by a distance-of 0.1 mm. If voltage across the plates is varying at the rate of 5 x 10 13 V/s then the value of displacement current is

    A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

    A plane e.m. wave of wave intensity 10 W,/m 2 strikes a small minor of area 20 cm 2 , held perpendicular to the approaching wave. The radiation force on the mirror will be

    A plane electromagnetic wave E z = 100 cos ⁡ 6 × 10 8 t + 4 x V / m propagates in a medium of refractive index

    A point source of electromagnetic radiation has an average power output of 800 W. The maximum value of electric field at a distance of 4.0 m from the source is

    The average energy density of electromagnetic wave given by E = ( 50 N / C ) sin ⁡ ( ωt − kx ) will be nearly

    Light with an energy flux of 19 W/ cm 2 falls on a non-reflecting surface at normal incidence’ If the surface has an area of 20cm 2 , the average force exerted on the surface during the span of 30 min is

    The electric field on an electromagnetic wave is given by E = ( 50 N / C ) sin ⁡ ω t − x c The energy contained in a cylinder of cross-section 10 cm 2 and length 50 cm along the x-axis will be

    The wavelength 21 cm emitted by atomic hydrogen in interstellar space belongs to

    Which of the following is electromagnetic wave

    Which of the following statement is wrong

    Electromagnetic waves are transverse in nature is evident by

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