Current Electricity — Physics STD 12 Science — Question

1. Find expressions for the force and torque on an electric dipole kept in a uniform electric field.

OR

An electric dipole is held in a uniform electric field. (i) Using suitable diagram show that it does not undergo any translatory motion, and (ii) derive an expression for torque acting on it and specify its direction.

2. Derive an expression for the work done in rotating a dipole from the angle $\theta_0$ to $\theta_1$ in a uniform electric field E.

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1. Define torque acting on a dipole of dipole moment $\vec{\text{p}}$ placed in a uniform electric field $\vec{\text{E}}.$ Express it in the vector form and point out the direction along which it acts.
2. What happens if the field is non-uniform?
3. What would happen if the external field $\vec{\text{E}}$ is increasing (i) parallel to $\vec{\text{p}}$ and (ii) anti-parallel to $\vec{\text{p}}?$