A neutron, a proton , and an electron and an alpha particle enter a region of constant magnetic field with equal velocities . The magnetic field is along the inward normal to the plane of the paper . The tracks of the particles are labelled in fig. the electron follows track .... and the alpha particle follows track.....

Answer

B, D

Explanation

According to Fleming's left hand rule , the force on electrons will be towards right (D). Also , by the same rule we find that the force on force on proton and ` alpha` - particle is towards left. Now since the magnetic force will behave as centripetal force, therfore
:. (mv^(2))/(r) = qvB
:. (mv)/(q^(B)) = r ` or ` r prop (m)/(q) `
For proton ` r prop 1/1 = 1 `, For `alpha `- particle ` r prop 4/2 = 2 `
:. radius will be more for `alpha`- particle
:. `alpha` - particle will take path `B`.