When a charged particle moves in a uniform magnetic field, its kinetic energy:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → remains unchanged
The force on a charged particle in a magnetic field is given by:
$\vec{F} = q \vec{v} \times \vec{B}$
Since $\vec{F}$ is always perpendicular to $\vec{v}$, the magnetic force does no work on the particle:
$W = \vec{F} \cdot \vec{d} = 0$
Work done = change in kinetic energy → kinetic energy remains unchanged.