A beam of electrons passes underfected throgh unifromly perpendicular electric and magnetic fields. If the electric fiedl is swiched off, and the same magnetic field is mainted fiedl is maintetained the electrons move:

Options

A. in a elliptical orbit
B. in a circular orbit
C. along a parabolic path
D. along a straight line

Answer

D

Explanation

Initially both the fields acts on the electrons and they passes through the deilds without any deviation. But if `vecE=0`, then only the magnetic field will act on the electrons and they will describes a circular path.