Question

Two identical charges of value Q each are placed at (–a, 0) and (a, 0). The co-ordinates of the points where net electric field is zero and maximum are respectively-

• A. (0, 0), (0, 0)
• B. (0, a/$\sqrt{2}$), (0, 0)
• C. (0, 0), (0, a/$\sqrt{2}$)
• D. (a/$\sqrt{2}$, 0), (0, a/$\sqrt{2}$)

Answer 1

Answer: (C)

(0, 0), (0, a/$\sqrt{2}$)

Answer 2

Net electric field will be zero at origin.

At any co-ordinate (0, y) E_Net = 2E cos 2q/2

=

For maximum electric field = 0

Solving y = ± a/$\sqrt { 2 }$