Question

Write the expression for the torque $$\overrightarrow{\tau }$$ acting on a dipole of dipole moment  $$\overrightarrow{p}$$ placed in an electric field $$\overrightarrow{E}$$.

Answer 1

The torque $$\overrightarrow{\tau }$$ acting on a dipole of dipole moment $$\overrightarrow{p}$$ placed in an electric field $$\overrightarrow{E}$$ is given by

$${\tau }^{\rightharpoonup }=\overrightarrow{p}\times E^{\rightharpoonup }$$

$$\text{ or }$$

$${\tau }^{\rightharpoonup }=pE\sin \theta$$

$$\text{ where }$$

$$\theta =\text{ Angle between dipole moment and electric field }$$