An electric dipole of dipole moment P is placed in a uniform electric field E with its axis making an angle of 37^circ with the field. The work requi…

Work done in rotating an electric dipole from angle $\theta_1$ to $\theta_2$ in a uniform electric field is $W = PE(\cos\theta_1 - \cos\theta_2)$. Here, $\theta_1 = 37^\circ$ and $\theta_2 = 180^\circ$. We know $\cos 37^\circ = 4/5 = 0.8$ and $\cos 180^\circ = -1$. Thus, $W = PE(0.8 - (-1)) = PE(0.8 + 1) = 1.8PE$.