# Capacitance Formula

Electrical capacitance is a property of objects that can hold electric charge. A capacitor is an electric component that results from creating a small gap between charge-carrying layers, for example, a parallel-plate capacitor. The capacitance is the collected charge divided by the voltage difference across the capacitor. Capacitance is measured in Farads (*F*), charge is measured in Coulombs (*C*), and voltage is measured in Volts (*V*). Be careful not to confuse capacitance: *C*, and the unit Coulombs: *C*.

C = capacitance (Farads, *F*)

Q = the charge built up on the capacitor (Coulombs, *C*)

V = voltage difference between two sides of a capacitor (Volts, *V*)

Capacitance Formula Questions:

1) In an electric circuit, a capacitor is holding a charge of 0.500 *C*. The voltage difference across the capacitor is 5.00 *V*. What is the capacitance?

Answer: The capacitance can be found using the formula:

C = 0.100 *F*

The capacitance is 0.100 *F*, which can also be written in milli-Farads: 100 *mF*.

2) The charge held on a small parallel-plate capacitor is 100 *μC *(micro-Coulombs). The voltage difference across the capacitor is 20.0 *mV* (milliVolts). What is the capacitance?

Answer: The charge is given in units of *μC*. One micro-Coulomb is equal to one one-millionth of a Coulomb: 1 *μC* = 1/1000000*C*. The voltage is given in units of *mV*. One milliVolt is equal to one one-thousandth of a Volt: 1 *mV* = 1/1000 *V*. Using these values, the capacitance can be found using the formula:

C = 0.00500 F

The capacitance is 0.00500 *F*, which can also be written in milli-Farads: 5.00 *mF*.

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