An electron is moving on a circular path of radius `r` with speed `v` in a transverse magnetic field B. e/m for it will be

Options

A. `(v)/(Br)`
B. `(B)/(rv)`
C. Bvr
D. `(vr)/(B)`

Answer

A

Explanation

As `qv B =(mv^(2))/(r) rArr "Radius", r=(mv)/(qB)`
For electron, `r=(mv)/(eB) :. (e)/(B)=(v)/(Br)`