Question:
A charged particle moves through a magnetic field perpendicular to its direction. Then
A charged particle moves through a magnetic field perpendicular to its direction. Then
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Magnetic force can change the direction of velocity but never its magnitude.
Hence:
K.E. = constant, Momentum (vector) = changing
Updated On: Mar 19, 2026
- kinetic energy changes but the momentum is constant
- the momentum changes but the kinetic energy is constant
- both momentum and kinetic energy of the particle are not constant
- both momentum and kinetic energy of the particle are constant
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The Correct Option is B
Solution and Explanation
Step 1: Magnetic force acting on a charged particle is given by: vecF = q(vecv × vecB)
Step 2: Since the force is always perpendicular to the velocity, it does no work on the particle. W = vecF · vecs = 0
Step 3: As no work is done, the kinetic energy remains constant.
Step 4: The force continuously changes the direction of velocity, hence the momentum vector changes (even though its magnitude remains constant).
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