Question

A particle of mass `M` and charge `Q` moving with velocity `vec(v)` describe a circular path of radius `R` when subjected to a uniform transverse magnetic field of induction `B`. The work done by the field when the particle completes one full circle is
A. ((Mv^(2)/( R )) 2 pi R `
B. `zero`
C. `B Q 2 pi R`
D. ` B Q v2pi R`

Answer 1

Correct Answer - B
The workdone, `dW = Fds cos theta`
The angle between force and displacement is `90^(@)` .
Therefore work done is zero.