KCET 2025 Physics Paper

The potential energy (PE) of an electric dipole in a uniform electric field is given by the formula:$PE = \overset{\rightarrow}{-p} \cdot \overset{\rightarrow}{E} = -p E \cos \theta$Let's evaluate the potential energy for different angles: (a) $\theta = 180^{\circ}$ :$PE = -p E \cos 180^{\circ} = p E$ This corresponds to option (ii) in Column-II.(b) $\theta = 120^{\circ}$ :$PE = -p E \cos 120^{\circ} = -p E \left(\frac{-1}{2}\right) = \frac{pE}{2}$ This corresponds to option (iii) in Column-II.(c) $\theta = 90^{\circ}$ :$PE = -p E \cos 90^{\circ} = 0$This corresponds to option (iv) in Column-II. Thus, the correct matching is:$a \rightarrow$ (ii)$b \rightarrow$ (iii)$c \rightarrow$ (iv)