Question

An electric dipole of moment p is placed parallel to the uniform electric field. The amount of work done in rotating the dipole by 90° is ____________.

Options

• 2pE

• pE

• pE/2

• Zero

Answer 1

An electric dipole of moment p is placed parallel to the uniform electric field. The amount of work done in rotating the dipole by 90° is pE.

Explanation:

`"W = pE" ("cos" theta_1 - "cos" theta_2)`

`theta_1 = 0^circ`

`theta_2 = 90^circ`

`"W = pE" ("cos" 0^circ - "cos"  90^circ)`

`= "pE" (1 - 0) = "pE"`