One of the exciting parts of this chapter is understanding how a charged particle behaves when it moves through a magnetic field. For example, it can travel in a circular path or even a spiral depending on the situation. This knowledge is used in devices like cyclotrons, which are particle accelerators, and in instruments that measure magnetic fields.
To help you prepare for exams, we have created a set of multiple-choice questions (MCQs) on this chapter. These questions cover all the important topics and test your understanding of the concepts. Each question comes with an answer and explanation, so you can learn from your mistakes and improve.
Practicing these MCQs will help you get a better grip on the chapter. It will also prepare you for board exams and competitive exams like JEE and NEET. Whether it’s solving numerical problems or understanding theoretical concepts, these questions will make your preparation easier and more effective.
So, start practicing and make sure you master the concepts of “Moving Charges and Magnetism.” It’s not just a chapter in your syllabus but also a gateway to understanding the wonders of electromagnetism!
MCQs with Answers
Question: Which of the following laws is used to determine the direction of magnetic force on a moving charge in a magnetic field?
A) Ohm’s Law
B) Fleming’s Left-Hand Rule
C) Biot-Savart Law
D) Ampere’s Law
Answer: B) Fleming’s Left-Hand Rule
Explanation: Fleming’s Left-Hand Rule is used to find the direction of the magnetic force experienced by a moving charge in a magnetic field.
Question: A charged particle moves in a magnetic field perpendicular to its velocity. What type of path will it follow?
A) Straight Line
B) Parabolic Path
C) Circular Path
D) Elliptical Path
Answer: C) Circular Path
Explanation: When a charged particle moves perpendicular to the magnetic field, it experiences a centripetal force that causes it to move in a circular path.
Question: The SI unit of the magnetic field is:
A) Tesla
B) Gauss
C) Weber
D) Ampere
Answer: A) Tesla
Explanation: The SI unit of the magnetic field is Tesla (T), which is equivalent to one Weber per square meter.
Also Check: NCERT Solutions for Class 12 Physics Chapter 4: Moving Charges and Magnetism
Question: What is the magnetic force on a stationary charge in a magnetic field?
A) Maximum
B) Minimum
C) Zero
D) Depends on the charge
Answer: C) Zero
Explanation: A stationary charge does not experience any magnetic force because the force depends on the motion of the charge (F = q(v x B)).
Question: Which device is used to measure the strength and direction of a magnetic field?
A) Galvanometer
B) Voltmeter
C) Ammeter
D) Magnetometer
Answer: D) Magnetometer
Explanation: A magnetometer is specifically designed to measure the strength and direction of magnetic fields.
Question: The force on a moving charge in a magnetic field is maximum when the angle between velocity and the magnetic field is:
A) 0°
B) 45°
C) 90°
D) 180°
Answer: C) 90°
Explanation: The magnetic force is given by F = qvB sinθ. It is maximum when θ = 90°.
Question: What is the formula for the radius of the circular path of a charged particle moving in a perpendicular magnetic field?
A) r = mv/qB
B) r = qvB/m
C) r = qB/mv
D) r = m/qvB
Answer: A) r = mv/qB
B) Velocity of the particle
C) Magnetic field strength
D) Mass of the particle
Answer: D) Mass of the particle
Explanation: Magnetic force depends on charge (q), velocity (v), and magnetic field (B), but not on the mass of the particle.
Question: What is the direction of the magnetic field inside a solenoid carrying current?
A) Circular around the axis
B) Perpendicular to the axis
C) Parallel to the axis
D) Opposite to the current direction
Answer: C) Parallel to the axis
Explanation: The magnetic field inside a solenoid is uniform and parallel to its axis, as determined by the right-hand rule.
Also Check: NCERT Exemplar Solutions for Class 12 Physics Chapter 4 – Moving Charges And Magnetism
Question: Which of the following quantities remains constant for a charged particle moving in a magnetic field?
A) Velocity
B) Kinetic Energy
C) Acceleration
D) Magnetic Force
Answer: B) Kinetic Energy
Explanation: In a magnetic field, the force does no work, so the kinetic energy of the particle remains constant.
Question : A current-carrying conductor placed in a uniform magnetic field experiences a force because of:
A) The charge in the conductor
B) The magnetic field produced by the conductor
C) The interaction of the conductor’s current with the external magnetic field
D) The electric field in the conductor
Answer: C) The interaction of the conductor’s current with the external magnetic field
Explanation: The force arises due to the interaction between the current in the conductor and the external magnetic field (Lorentz force).
Question: The magnetic moment of a current loop depends on:
A) The number of turns, current, and area of the loop
B) Only the area of the loop
C) Only the current in the loop
D) The magnetic field strength
Answer: A) The number of turns, current, and area of the loop
Explanation: Magnetic moment (
) is given by
, where
is the number of turns,
is the current, and
is the area.
Question: The force between two parallel current-carrying conductors is:
A) Always attractive
B) Always repulsive
C) Attractive if currents are in the same direction
D) Repulsive if currents are in the same direction
Answer: C) Attractive if currents are in the same direction
Explanation: Parallel currents in the same direction attract each other due to the magnetic field interaction.
Question: If the length of a current-carrying conductor in a magnetic field is doubled, the force acting on it:
A) Remains the same
B) Doubles
C) Halves
D) Becomes zero
Answer: B) Doubles
Explanation: The magnetic force is
, so if
is doubled,
also doubles.
Question: What is the magnetic field at the center of a circular current-carrying loop of radius
and current
?
A)
B)
C)
D)
Answer: B)
Explanation: The magnetic field at the center of a current loop is given by
.
Question: What happens to the radius of a charged particle’s circular path if the magnetic field strength is doubled?
A) Doubles
B) Halves
C) Remains the same
D) Becomes zero
Answer: B) Halves
Explanation: The radius of the circular path is inversely proportional to the magnetic field strength (
).
Question: Which device operates on the principle of converting electrical energy into mechanical energy using a magnetic field?
A) Transformer
B) Galvanometer
C) Electric Motor
D) Ammeter
Answer: C) Electric Motor
Explanation: An electric motor converts electrical energy into mechanical energy using the interaction between current and magnetic fields.
Question : A charged particle enters a region with both electric and magnetic fields, and moves undeflected. What is the condition for this?
A) Electric field equals magnetic field
B) Magnetic force equals electric force
C) Electric field is perpendicular to the magnetic field
D) Electric force is zero
Answer: B) Magnetic force equals electric force
Explanation: For a particle to move undeflected,
, or
, ensuring the forces balance each other.
