A capacitor is fully charged with a battery and then disconnected. A dielectric is then inserted into the capacitor. How do charges on surface of the dielectric and outer surface of the plates of the capacitor would change respectively?

Question

A capacitor is fully charged with a battery and then disconnected. A dielectric is then inserted into the capacitor. How do charges on surface of the dielectric and outer surface of the plates of the capacitor would change respectively? (A) increases, decreases (B) decreases, increases (C) increases, remain unchanged (D) remains unchanged, increases

Tardigrade Admin · Accepted Answer

As capacitor is disconnected from battery. Its charges at the plates will get stored in the form of electrostatic energy (Case I).

When a dielectric is introduced inside this capacitor, it gets polarised as shown in (Case II).
Due to this, charges at surface of dielectric gets increased.
Since, there is no external electric supply of power source.
Hence, charges on capacitor remains unchanged.

Q. A capacitor is fully charged with a battery and then disconnected. A dielectric is then inserted into the capacitor. How do charges on surface of the dielectric and outer surface of the plates of the capacitor would change respectively?

increases, decreases

decreases, increases

increases, remain unchanged

remains unchanged, increases