The torque exerted by an electric field on a dipole is?

Parallel to the field and perpendicular to the dipole moment

Parallel to both the field and the dipole moment

Perpendicular to both the field and the dipole moment

Parallel to the dipole moment and perpendicular to the field

Explanation

When a dipole with dipole moment $vec{p}$ is placed in an external electric field $vec{E}$ , the torque experienced by the dipole is given by:

$vec{tau} = vec{p} times vec{E}$

This is a vector cross product, so:

The magnitude is $tau = pE sintheta$
The direction is perpendicular to both $p$ and $E$ (using the right-hand rule)