Question

work done in rotating a dipole in uniform magnetic
field

Answer 1

Dipole is two opposite charges seperated by a fixed distance. When it is kept in electric field as shown below-

Direction of force due to electric field acts in opposite direction which is responsible for giving torque to rotate it, if it is kept at an angle w.r.t direction of electric field. To rotate it in opposite direction of torque produced due to electric field, some work is to be done.

This work done is given by dw=T*d(theta)

T=torque at any particular angle =E*q*d*sin(theta)

total work done = [INT] (dw)=[INT](E*q*d*sin(theta)*d(theta) { from theta=0 to 180 degree)

=E*q*d*(- 1-1)= 2Eqd will be the required answer.