A electric dipole has the magnitude of its charge as $q$ and its dipole moment is $p$. It is placed in a…
A electric dipole has the magnitude of its charge as $q$ and its dipole moment is $p$. It is placed in a uniform electric field $E$. If its dipole moment is along the direction of the field, the force on it and it and its potential energy are respectively:
2 q.E and minimum
$q \cdot E$ and $p . E$
zero and minimum
$q \cdot E$ and maximum
Solution
Force on each charge, of dipole $F=$ $p E$
$\therefore$ Total force $=$ zero, they are in opposite director
$\therefore \vec{P}$ and $\vec{E}$ are parallel to each other
$\therefore \quad U=-\vec{P} \cdot \vec{E}$ is minimum.