Question

3. An electric dipole of moment p is placed parallel to the uniform electric field. The amount of work done in rotating the dipole by 180° is- (a) 2pE. (b) pE. (c) pE/2 (d) Zero ​

Answer 1

The amount of work done in rotating a dipole by 180 degree is a)2PE

EXPLANATION:-

work done by external agent in rotating the dipole is

W=PE[cos(theta1) -cos(theta2)]

considering the initial angle to be 0° and final angle to be 180°

So, W=PE[cos0°-cos180°]=2PE

Hope it helps!!