An electric dipole 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 `theta= 90^(@)`, the torque and the potential energy of the dipole will respectively be

Options

A. `pE sin theta , -p E 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

Explanation

`vec(tau) = vec(p) xx vec(E )`
`tau = p E sin theta`
`U = - p E sin theta`
` U = - p E cos theta`