Free Charged Particle in a Magnetic Field MCQs with Answers
62 Charged Particle in a Magnetic Field MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
A charged particle moving through a magnetic field experiences the Lorentz force, which is perpendicular to both its velocity and the field. The motion may be circular or helical, with questions involving radius, angular frequency, time period, and work done. A stationary charge feels no magnetic force.
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- A. It will also double
- B. It will be halved
- C. It will increase four times
- D. Remain unchanged
Explanation: It will remain unchanged. As the frequency of revolution in a cyclotron υC=Bq2πm is independent of r.
Correct answer: Remain unchanged- A. Proton
- B. Alpha particle
- C. Photon
- D. All of these options are correct
Explanation: The magnitude of deflection depends upon two factors: The mass (m) of the ion - the lighter it is the more it will be deflected.
Correct answer: Proton- A. Circular
- B. Straight line
- C. Spherical
- D. Helical
Explanation: Force is given by F = qvBsinθ, where F, q, v and B are the force, charge on particle, velocity of particle and magnetic field strength…
Correct answer: Helical- A. Moves in the direction of the field
- B. Moves perpendicular to the direction of the field
- C. Moves opposite to the direction of the field
- D. Remains stationary
Explanation: A strong magnetic field is applied to a stationary electron. Then the electron remains stationary because magnetic force act on moving…
Correct answer: Remains stationary- A. Decreases
- B. Increases then decreases
- C. Becomes zero
- D. Remains constant
Explanation: When a charged particle enters a strong magnetic field, its kinetic energy remains constant.
Correct answer: Remains constant- A. deflect upwards
- B. deflect downward
- C. speed up
- D. speed down
Explanation: Option C is correct since over here the velocity vector and magnetic field vector are in the same direction so there is no magnetic force.
Correct answer: speed up- A. f= mB/πC
- B. f= 2πeB/m
- C. f= eB/2πm
- D. f= 2πc/mB
Explanation: For a cyclotron Centripetal force is provided by magnetic force.By derivation, A, B & C are wrong.
Correct answer: f= eB/2πm- A. If an electron's movement is parallel to the magnetic field, it will experience no force.
- B. If an electron's movement is parallel to the magnetic field, it will rotate anticlockwise.
- C. If an electron enters perpendicular to the magnetic field, it will move in a circular path.
- D. If an electron enters perpendicular to the magnetic field, the force experienced will be maximum.
Explanation: The correct answer is Option D: If an electron enters perpendicular to the magnetic field, the force experienced will be maximum.
Correct answer: If an electron's movement is parallel to the magnetic field, it will rotate anticlockwise.- A. Hyperbola
- B. Helix
- C. Parabola
- D. Circular
Explanation: If a charged particle is projected perpendicular to a uniform magnetic field, then the particle revolves in a circular path and its…
Correct answer: Circular- A. qBr
- B. qB/r
- C. q/(Br)
- D. B
Explanation: Here the centripetal force will balance the magnetic force. So, mv2/r=qvB or mv=qBr Thus, linear momentum, p=mv=qBr
Correct answer: qBr- A. Up
- B. Down
- C. Right
- D. Towards us
Explanation: The correct answer is D. When a proton enters a magnetic field vertically upward from the left side, it experiences a force perpendicular…
Correct answer: Towards us- A. Parabolic
- B. Circular
- C. Parallel to v
- D. Parallel to B
Explanation: The magnetic force will act perpendicular to velocity at every instant ,path will be circle.
Correct answer: Circular- A. Towards the outward
- B. Towards the inward
- C. Parallel to its motion
- D. No force acts on it
Explanation: The electron is moving along the axis with velocity V Force = q(V x B) Velocity and magnetic field are in the same direction or at an…
Correct answer: No force acts on it- A. Minimum
- B. Maximum
- C. Zero
- D. Negative
Explanation: The work done on a charged particle moving in a uniform magnetic field is zero.
Correct answer: Zero- A. Radially inward
- B. Radially outward
- C. Zero
- D. Parallel to axis of solenoid
Explanation: The correct option for the question is Zero. When a proton is moving along the axis of a solenoid, the magnetic force on the proton is…
Correct answer: Zero- A. qvB sinθ
- B. qvB cosθ
- C. qvB
- D. Zero
Explanation: The magnetic force on a charge is given by the Lorentz force law, which can be stated as: F=q(v×B)where:F is the magnetic force,q is the…
Correct answer: Zero- A. Electric Field applied in direction of motion
- B. Electric Field applied perpendicular to direction of motion
- C. Magnetic Field applied in direction of motion
- D. Magnetic Field applied perpendicular to direction of motion
Explanation: Here is the explanation of the correct optionF = q(v x b)As v & b are in same direction so their cross product is zero F = q (0)F = 0(The…
Correct answer: Magnetic Field applied in direction of motion- A. 3 N.
- B. 4 N.
- C. 5 N.
- D. 6 N.
Explanation: F = QvBsin(θ)Where: * F is the magnetic force * Q is the charge of the particle * v is the velocity of the particle * B is the magnetic…
Correct answer: 6 N.- A. 1.6 x 10^-25 N.
- B. 1.6 x 10^-13 N.
- C. 1.6 x 10^13 N.
- D. 1.6 x 10^25 N
Explanation: The magnetic force on a charged particle moving perpendicular to a magnetic field is calculated using the formula F = qvB, where q is the…
Correct answer: 1.6 x 10^-13 N.- A. Mass.
- B. Volume.
- C. Direction of motion.
- D. Energy in the system.
Explanation: When a charged particle moves through a magnetic field, it experiences a magnetic force that acts perpendicular to both its velocity and…
Correct answer: Direction of motion.