question_answer

An electric dipole is placed in an uniform electric field with the dipole axis making an angle                                                                                  \[\theta\] with the direction of the electric field. The orientation of the dipole for stable equilibrium is:

A)                                                                             \[\frac{\pi }{6}\]                                    

B)                                                                             \[\frac{\pi }{3}\]  

C) 0                                 

D)                                                                             \[\frac{\pi }{2}\]

Correct Answer: C

Solution :

(c) 0 For stable equilibrium, the angle                                                                                  \[\theta\]  should be zero.                                                                  \[\tau =pE\,\sin \theta =pE\,\sin \theta =0\]