Electrostatic Potential and Capacitance - Result Question 18
20. An electric dipole has the magnitude of its charge as $q$ and its dipole moment is $p$. It is placed in uniform electric field $E$. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively[2004]
(a) $q \cdot E$ and max.
(b) $2 q . E$ and $min$.
(c) $q . E$ and $p . E$
(d) zero and $min$.
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Answer:
Correct Answer: 20. (d)
Solution:
- (d) When the dipole is in the direction of field then net force is $q E+(-q E)=0$
and its potential energy is minimum
$=-$ P.E. $=-q a E$
