Question

If a proton enters a region of uniform magnetic field with velocity $v$ in a direction perpendicular to the magnetic field, then the time period of revolution is $T$. If proton enters with velocity $2v$, the time period will be

• A. $2T$
• B. $3T$
• C. $4T$
• D. $T$

Answer 1

The correct option is D $T$

Time period of revolution for moving charge $q$ and mass $m$ with velocity $v$ in uniform magnetic field $B$ is given by

$T=\frac{2\pi m}{qB}$

Here, we can see that $T$ is independent on $v$.

So, for any velocity, time period will remain same.

Why this question: to know the quantities on which time period depends and its relation with them.