Question

A charged particle enters a uniform magnetic field with a certain speed at right angles to it. In the magnetic field a change could occur in its

• A. kinetic energy
• B. angular momentum
• C. linear momentum
• D. speed

Answer 1

Answer: (C)

Force acting on particle due to magnetic field $B$ is
$F=q\vec{v}\times \vec{B}$...(i)
and centripetal force is $F=\frac{m{v}^2}{r}$...(ii)
From Eqs. (i) and (ii), we get
$B=\frac{mv}{rq}=\frac{\text{ linear momentum }}{\text{ charge }}$