Question

An electric dipole of moment 'p' is placed in an electric field of intensity 'E'. The dipole acquires a position such that the axis of the dipole makes an angle $\theta$ with the direction of the field. Assuming that the potential energy of the dipole to be zero when=${90}^0$, the torque and the potential energy of the dipole will respectively be

• A. $pE\sin \theta ,pE\cos \theta$
• B. $pE\sin \theta ,-2pE\cos \theta$
• C. $pE\sin \theta ,2pE\cos \theta$
• D. $pE\cos \theta ,-pE\cos \theta$

Answer 1

The correct option is A $pE\sin \theta ,pE\cos \theta$

An electric dipole of moment $=P$

electric field of intensity $=E$

the dipole acquire a position angle $=\theta$

dipole to be zero when $={90}^0$

torque and the potential energy of the dipole will respectively

potential energy $U=PE\sin \theta$ in this situation.

$SIn$ component is benefited for that, perpendicularity and dipole is hence, $PEcos\theta$