Question

A particle of charge $e$ and mass $m$ moves with a velocity $v$ in a magnetic field $B$ applied perpendicular to the motion of the particle. The radius $r$ of its path in the field is

• A. $\frac {mv}{Be}$
• B. $\frac {Be}{mv}$
• C. $\frac {ev}{Bm}$
• D. $\frac {Bv}{em}$

Answer 1

Answer: (A)

$\frac {mv}{Be}$

Answer 2

Radius of path, $r=\frac{m v}{q B}$
Here, $q=e$
So, $r=\frac{m v}{e B}$