Capacitance (C) is the constant of proportionality between the charge (Q) stored on a capacitor and the potential difference (V) between its plates: $C = \frac{Q}{V}$

A capacitor is a device that stores electrical charge and potential energy in an electric field.

The Farad (F) is the unit of capacitance, defined as 1 F = 1 C/V.

The potential difference (V) is the difference in electric potential between two points, which is proportional to the charge stored on a capacitor.

Charge (Q) is the electrical charge stored on the plates of a capacitor.

1. Find the electric field using Gauss's Law. 2. Calculate the potential difference using $\Delta V = - \int E \cdot dr$. 3. Use $C = \frac{Q}{V}$ to find the capacitance.

1. Identify the known variables (Q, V, and/or C). 2. Choose the appropriate formula: $U_c = \frac{1}{2} QV$, $U_c = \frac{1}{2} CV^2$, or $U_c = \frac{Q^2}{2C}$. 3. Plug in the values and calculate $U_c$.

A is the area of the plates, d is the distance between the plates.