The dipole moment of a dipole in an uniform external field (... | Physics | SolveeIt

Question

The dipole moment of a dipole in an uniform external field $\vec{E}$ is $\vec{P}$ . Then, the torque $(\tau )$ acting on the dipole is

$\vec{\tau }=\vec{P}\times \vec{E}$

$\vec{\tau }=\vec{P}.\vec{E}$

$\vec{\tau }=2(\vec{P}+\vec{E})$

$\vec{\tau }=(\vec{P}+\vec{E})$

Answer

$\vec{\tau }=\vec{P}\times \vec{E}$

Explanation

Solution

Torque $(\tau)$ acting on the dipole in an uniform external field $E$
$\tau=$ either force $\times$ perpendicular distance
$=q E \times 2 a \sin \theta$
$=(q \times 2 a) \times E \sin \theta$
$=P E \sin \theta$
or $\tau=P \times E$

Physics Question on Electric Dipole

Solution