A parallel-plate capacitor is connected to a battery until it is fully charged. Then, teh capacitor is disconnected from the battery and connected to two uncharged parallel plates that make up a capacitor. The potential between the plates of the initial capacitor will:

a. increase.

b. decrease.

c. stay the same.

Briefly explain why.

The potential between the plates of the initial capacitor will:

b). decrease

Explanation:

A capacitor is made up a material which is an insulator placed between the parallel plate. This insulator is known as a dielectric which increases the amount of charge a capacitor can store at a give potential difference. This dielectric reduces the electric field of a charged capacitor not connected to a supply.

When a fully charged capacitor is disconnected from a battery and connected to two uncharged parallel plates, the potential between the plates of the initial capacitor decreases with the charge remaining the same. This is because the added uncharged capacitor increases the capacitance of the charged capacitor by a factor, and since the charge is the same the potential difference decreases.

From Δvd = q/C where q is charge, C is capacitance and Δvd is potential difference, an increase in capacitance with charge constant reduces the potential difference.