Electron oving with different speeds enters a transverse uniform magnetic field. They will describe circular path

Options

A. of the same radius
B. of larger radii for the faster electrons
C. of smaller radii for the faster electrons
D. either (b) or (c ) depending on the magnitude of the magnetic field

Answer

B

Explanation

Force acting on the electron=Bqv=Bev and this provides the C.P. force `(mv^(2))/r therefore (mv^(2))/r=Bev therefore r=(mv)/(Be)=(m/Be)v` But B, m and e are the same for all electron. `therefore r propto v therefore` Faster electrons will describe circular paths of larger radii.