A sample of HCl gas is placed in an electric field of $3 × 10^4 NC^{-1}$. The dipole moment of each HCl molecule is $6× 10^{-30} Cm$. The maximum torque that can act on this molecule is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $1.8×10^{-26} N m$
The torque $(τ)$ acting on a dipole in uniform electric field is -
$τ=pE\sin θ$
where,
Dipole moment, $p=6×10^{-30}$
Electric field, $E=3×10^4N/C$
The maximum torque occurs when $\sin θ=1$ is -
$τ_{max}=pE$
$=(6×10^{-30})(3×10^4)$
$=1.8×10^{-26} N m$