An electron is projected with velocity vec v in a uniform magnetic field vec B . angle θ &nbs

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4.Moving Charges and Magnetism

medium

An electron is projected with velocity $\vec v$ in a uniform magnetic field $\vec B$ . The angle $\theta$ between $\vec v$ and $\vec B$ lines between $0^o$ and $\frac{\pi}{2}$ . It velocity $\vec v$ vector returns to its initial value in time interval of

A

$\frac{2 \, \pi m}{eB}$

B

$\frac{ \pi m}{eB}$

C

$\frac{ \pi m}{2\,eB}$

D

Depends upon angle between $\vec v$ and $\vec B$

Solution

The electron will move in a circular path The velocity vector returns to its initial value in a time period.

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

Standard 12

Physics

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