Physics · Electrostatic Potential

A substance contains 1 mole of molecules, each having a permanent dipole moment of \( 10^{-29}\ \text{C}\cdot\text{m} \). The sample is polarised by an electric field of \( 10^6\ \text{V}\cdot\text{m}^{-1} \) aligned with the field. The direction of the field is suddenly rotated by \( 60^\circ \). Assuming \( 100\% \) polarisation, the heat released by the substance when dipoles realign with the new field is: (Given \( N_A = 6 \times 10^{23} \))

1. \( 6\text{ J} \)
2. \( 3\text{ J} \)
3. \( 9\text{ J} \)
4. \( 12\text{ J} \)