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When placed in a uniform external electric field, an electric dipole experiences
Aa net force but no torque
Bboth a net force and a net torque
Cneither force nor torque
Da torque but no net force
Answer & Solution
Correct answer: D. a torque but no net force
1. The forces on $+q$ and $-q$ in a uniform field are equal and opposite, so the **net force is zero**.
2. These forces form a couple, giving a torque $\vec{\tau} = \vec{p}\times\vec{E}$, magnitude $pE\sin\theta$.
3. Thus a dipole in a uniform field only rotates; it does not translate.
_Source: Samacheer Kalvi Class 12 Physics Vol.1, Unit 1 'Electrostatics', §1.4.3_
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