Question

Maximum torque acting on an electric dipole of moment $3\times {10}^{-29}$Cm in a uniform electric field E is $6\times {10}^{-25}$Nm. Find E.

Answer 1

torque acting on an electric dipole is given by

$\Rightarrow \tau =PE\sin \theta$

for maximum torque, $\theta ={90}^{\circ }$

$\Rightarrow {\tau }_{max}=PE$

$\Rightarrow E=\frac{{\tau }_{max}}{P}$

$\Rightarrow E=\frac{6\times {10}^{-25}}{3\times {10}^{-29}}=2\times {10}^4$$N{C}^{-1}$