Question

The potential energy of a charged parallel plate capacitor is $U_0$. If a slab of dielectric constant $K$ is inserted between the plates, then the new potential energy will be

• A. $ \frac{U_{0}}{K} $
• B. $ U_{0}K^{2} $
• C. $\frac{U_{0}}{K^{2}}$
• D. $U_{0}^{2}$

Answer 1

Answer: (A)

When a dielectric slab of dielectric constant $K$ is inserted between the plates of charged parallel plate capacitor, then
capacity becomes $C'=K C$
potential becomes $V'=\frac{V}{K}$
and energy $U'=\frac{U}{K}$