Question

An electron and a proton moving parallel to each other in the same direction with equal momenta enter into a uniform magnetic field which is at right angles to their velocities. Trace their trajectories in the magnetic field.

Answer 1

Since \(\frac{mv^2}{r} \)  = q v B

∴ r = \(\frac{mv}{q\ B}\)

Both will have circular trajectories but in opposite directions.