Question

For an electric dipole in a non-uniform electric field with dipole moment parallel to direction of the field, the force $F$ and torque $\tau$ on the dipole respectively are __________. Fill in the blank with the correct answer from the options given below.

• A. $F = 0$, $\tau = 0$
• B. $F \neq 0$, $\tau = 0$
• C. $F = 0$, $\tau \neq 0$
• D. $F \neq 0$, $\tau \neq 0$

Hint:

Remember: 1. In a uniform field: $F$ is always $0$, $\tau$ depends on the angle. 2. In a non-uniform field: $F$ is always $\neq 0$, $\tau$ depends on the angle. If $\vec{p}$ is parallel or anti-parallel to $\vec{E}$, torque is always zero!

Answer 1

The Correct Option is B