When an electric dipole $P$ is placed in a uniform electric field $E$ then at what angle between $\vec{P}$…
When an electric dipole $P$ is placed in a uniform electric field $E$ then at what angle between $\vec{P}$ and $\vec{E}$ the value of torque will be maximum?
$90^{\circ}$
$0^{\circ}$
$180^{\circ}$
$45^{\circ}$
Solution
$\vec{\tau}=\overrightarrow{\mathrm{P}} \times \overrightarrow{\mathrm{E}}=\mathrm{PE} \sin \theta$
For $\mathrm{q}=90^{\circ}, \vec{\tau}_{\max }=\mathrm{PE}$