# Video: Calculating the Capacitance Required to Store a Particular Charge

What capacitance is needed to store 3.00 ๐C of charge at a voltage of 120 V?

01:30

### Video Transcript

What capacitance is needed to store 3.00 microcoulombs of charge at a voltage of 120 volts?

We can call the charge value of 3.00 microcoulombs ๐. And letโs name the voltage value, 120 volts, ๐. We want to solve for the capacitance of the system thatโs needed to store this much charge ๐ at this much voltage ๐. Weโll call that capacitance ๐ถ. Letโs start off by recalling the mathematical definition of capacitance.

Capacitance is the capability of a system to store some amount of charge ๐ at some voltage level ๐. The more charge there is in a system, the more capacitance that system has to contain all that charge. On the other hand, as potential difference decreases in a system, capacitance goes up in order to account for the small potential difference separating the charges in the system. The capacitance of our system is ๐ over ๐ or 3.00 times 10 to the negative sixth coulombs divided by 120 volts.

When we calculate this fraction, we find that, to three significant figures, the systemโs capacitance is 25.0 nanofarads. Thatโs the capacitance needed to store this much charge at this much voltage.