Question

An electric dipole consists of two oppositecharges of magnitude 1$\mu C$ separated by a distanceof 2$cm.$ The dipole is placed in an electric filed${10}^{-5}{Vm}^{-1}$ . The maximum torque does the field exerton the dipole is

• A. ${10}^{-3}Nm$
• B. $2\times {10}^{-13}Nm$
• C. $3\times {10}^{-13}Nm$
• D. $4\times {10}^{-13}Nm$

Answer 1

Answer: (B)

$2\times {10}^{-13}Nm$

The formula is$:$

$Torque\left(\tau \right)=pE\sin \theta$

here$,$ $E={10}^{-5}$

$\theta ={90}^0$

$p=q\times 2d$

$={10}^{-6}\times 2\times {10}^{-2}$

$p=2\times {10}^{-8}$

substitutes all the known values$,$

$\tau =2\times {10}^{-8}\times {10}^{-5}\times 1$ $\left(\because \sin {90}^0=1\right)$

$\tau =2\times {10}^{-13}Nm.$

Hence,

option $\left(B\right)$ is correct answer.