Q. A sample of HCl gas is placed in an electric field of $3 \times 10^{4}NC^{- 1}$. The dipole moment of each HCl molecule is $6 \times 10^{- 30}$Cm. The maximum torque that can act on a molecule is
A) $2 \times 10^{- 34}C^{2}mN^{- 1}$
B) $2 \times 10^{- 34}$Nm
C) $18 \times 10^{- 26}$Nm
D) $0.5 \times 10^{34}C^{- 2}Nm^{- 1}$
Explanation
(c) Torque,
$\tau = p \times E\ $
$\tau_{\max\ } = pE = 6 \times 10^{- 30} \times 3 \times 10^{4}$
$= 18 \times 10^{- 26}Nm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.