A proton moving with a constant velocity passes through a region of space without any changing its velocity. If `E` and `B` represent the electric and magnetic fields, respectively. Then, this region of space may have

Options

A. I,ii and iii
B. ii,iii and iv
C. I,ii and iv
D. all

Answer

C

Explanation

Here the proton has no accedleration so `E = B = 0`. When `E = 0` but `B != 0`, but parallel to the motion of proton, there will be no force acting,n When `E != 0` and `E,B` and motion of proton `(v)` are mutually perpendicular, there may be no net force. Forces due to the `E` and `B` cancel each other.