By inserting a plate of dielectric material between the plates of a parallel plate capacitor at constant potential, the energy stored in the capacitor is increased five times. The dielectric constant of the material is

• A. 5
• B. 1/5
• C. 25
• D. 1/25

Answer: (A)

Energy stored by capacitor, Q = ½CV²
Dielectric constant is directly proportional to C and capacitance is proportional to the dielectrical constant