Q. An electric dipole consists of two opposite charges, each of magnitude 1.0 $\mu$C separated by a distance of 2.0 cm. the dipole is placed in an external electric field of 10$^{5}$ NC$^{-1}$. The maximum torque on the dipole is
A) 0.2$\times 10^{- 3}$N-m
B) 1$\times 10^{- 3}$N-m
C) 2$\times 10^{- 3}$N-m
D) 4$\times 10^{- 3}$N-m
Explanation
(c) $\tau_{\max} = p\ E\sin 90^{0}$
$= q(2a)E = 10^{- 6} \times 2 \times 20^{- 2} \times 10^{\begin{array}{r}
5 \\
\
\end{array}}$
$2 \times 10^{- 3\ }Nm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.