A dipole of dipole moment $\overrightarrow p $ is placed in uniform electric field $\overrightarrow E $ then torque acting on it is given by
$\overrightarrow \tau = \overrightarrow p .\overrightarrow E $
$\overrightarrow \tau = \overrightarrow p \times \overrightarrow E $
$\overrightarrow \tau = \overrightarrow p + \overrightarrow E $
$\overrightarrow \tau = \overrightarrow p - \overrightarrow E $
