An 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 its potential energy are respectively

Options

A. `2q.E` and minimum
B. `q.E` and `p.E`
C. zero and minimum
D. `q.E` and maximum

Answer

3

Explanation

`tau = pE sin 0^(@) = 0`
`U = -pE cos 0^(@) = -pE = U_(min)`