Question

In a uniform electric field the maximum torque acting on an electric dipole is $\tau$.

• A. $qaE$
• B. $\frac{\sqrt{3} q a E}{2}$
• C. $2qaE$
• D. Zero

Answer 1

Answer: (A)

$\overset{ \rightarrow }{\tau}=\overset{ \rightarrow }{P}\times \overset{ \rightarrow }{E}$
$\left|\right.\overset{ \rightarrow }{\tau}\left|\right.=\left|\right.\overset{ \rightarrow }{P}\left|\right.\left|\right.\overset{ \rightarrow }{E}\left|\right.sin\theta $
$\left|\right.\overset{ \rightarrow }{\tau}\left|\right._{m a x}=\left|\right.\overset{ \rightarrow }{P}\left|\right.\left|\right.\overset{ \rightarrow }{E}\left|\right.=qaE$