Question

An electric dipole is placed at an angle of ${30}^{\circ }$ withan electric field intensity $2\times {10}^{5}N/C$ . It experiencesa torque equal to 4$N$ . The charge on the dipole, ifthe dipole length is $2cm,$ is

• A. 8$\mu C$
• B. 2$\mu C$
• C. 5$\mu C$
• D. 7$\mu C$

Answer 1

The correct option is A 8$\mu C$

$T$ experienced $f\times r_1$

$\begin{array}{c}=qW\times r_1\\ q\times 2\times {10}^5\times \frac{2}{100}\sin 30\\ 4N=q\times 2\times {10}^3\\ q=\frac{2}{{10}^3}=2mC\end{array}$