Q.

An electric dipole of dipole moment 6×10–6 cm is placed in uniform electric field of magnitude 106 V/m. Initially, the dipole moment is parallel to electric field. The work that needs to be done on the dipole to make its dipole moment opposite to the field, will be ______ J.          [2025]


Ans.

(12)

Work done in rotating a dipole =△U

or W=(–PE cos θf)–(–PE cos θi)

            =2PE                                                 (∵ θf=180° and θi=0°)

            =(2×6×10–6×106)J=12 J