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Question
A charged particle is in motion having initial velocity `vecv` when it enters into a region of uniform magnetic field perpendicular to `vecv`. Because of the magnetic force the kinetic energy of the particle will ______.
Options
remain unchanged
get reduced
increase
be reduced to zero
Solution
A charged particle is in motion having initial velocity v when it enters into a region of uniform magnetic field perpendicular to v. Because of the magnetic force the kinetic energy of the particle will remain unchanged.
Explanation:
The work done by the magnetic force is always zero because the direction of motion due to the magnetic force is always perpendicular to it. When the particle enters the field the magnitude of the velocity stays the same while the direction changes and while the kinetic energy remains the same. It can only lead to a change in the direction of motion and not the speed. Hence there is going to be no change in the kinetic energy of the particle.
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