Question

In a uniform electric field $10\text{ N C}^{-1}$, an electric dipole of length $4\text{ cm}$ is placed with its axis making an angle $60^\circ$ with the electric field. If the dipole experiences a torque of $8\sqrt{3}\text{ N m}$, find the potential energy of the dipole.

• A. $8\text{ J}$
• B. $-8\text{ J}$
• C. $-16\text{ J}$
• D. $16\text{ J}$

Hint:

You can directly link torque and potential energy for any system when given the same angle by using the simple identity: $U = -\tau \cot\theta$. Here, $U = -(8\sqrt{3}) \cot(60^\circ) = -8\sqrt{3} \times \frac{1}{\sqrt{3}} = -8\text{ J}$. This completely bypasses finding $p$ or $E$ explicitly!

Answer 1

The Correct Option is B