Question

A particle moving with constant velocity passes through a region of space without any change in its velocity. If E and B represent electric and magnetic fields respectively, this region of space may have

• A. E = 0 and B = 0
• B. E = 0 and $B\ne 0$
• C. $E\ne 0$ and B = 0
• D. $E\ne 0$ and $B\ne 0$

Answer 1

Answer: (A), (B), (D)

The correct options are
A E = 0 and B = 0
B E = 0 and $B\ne 0$
D $E\ne 0$ and $B\ne 0$

Magnetic field act perpendicular to velocity and do not change its speed but changes its direction. So Velocity will remain same even if there is magnetic field is there. Electric field act along the electric line and will change the velocity , So keep velocity same E must be zero or Electric force must be balance by magnetic force.