A proton is moving in a uniform electric field E, of unknown magnitude and direction.There is a uniform magnetic field of 0.01T pointing in the y-direction. The proton moves in the x direction at a constant velocity of 10km/s.

Options

A. E=100V/m, in the z direction
B. E=100 V/m, in the negative z direction
C. E=100V/m, in the x direction
D. E=100V/m, in the negative y direction

Answer

B