If an electron and a proton having same momenta enter perpendicular to a magnetic field, then

Options

A. they will move undeflected
B. curved path of the electron and the proton will be the same (ignoring the sense of revolution)
C. the path of proton is more curved then that of the electron
D. curved path of the electron is more curved than that of the proton

Answer

B

Explanation

The force produced by the magnetic feild on a charged particle is `F=qvB` and this gives the C.P force `(mv^(2))/r therefore (mv^(2))/r=qvB therefore r=(mv)/(qB)=p/(qB)` where p=momentum` Thus for both the particle,p,q and B are of the same magnitude. Hence they will have the same r or they will describe the same curved path. [One will move colckwise and the other anticlockwise.]