A certain capacitor stores 30 J of energy when it holds 4811

A certain capacitor stores 30 J of energy when it holds 4,811 uC of charge. What is the capacitance in nF

Solution

Energy U = 30 J

Charge q = 4811 x10 ^-6 Coulomb

Capacitance C = ?

We know U = q ² /2C

From this capacitance C = q ²/2U

                                    = (4811 x10 ^-6) ² / [2 x30]

                                    = (2.314 x10 ^-5 ) / 60

                                    = 385.76 x10 ^-9 F

                                    = 385.76 nF