Question

A parallel plate capacitor with air as dielectric has a capacitance of 4 $\mu$F. The space between the plates of the capacitor is completely filled with a material of dielectric constant 5 and charged to a potential of 100 V. The work done to completely remove the dielectric material after the capacitor is disconnected from the battery is

• A. 0.1 J
• B. 0.5 J
• C. 0.6 J
• D. 0.4 J

Hint:

When a capacitor is disconnected from the battery, its charge ($Q$) remains constant. When it remains connected, its voltage ($V$) remains constant. The work done to change the configuration (e.g., remove a dielectric) is the change in the stored potential energy, $W = \Delta U = U_{final} - U_{initial}$.

Answer 1

The Correct Option is D