The Capacitor
Part of the Electricity and Magnetism section of Coddy's Physics journey. Lesson 17 of 51.
A capacitor stores equal and opposite charges on two conductors. Its capacitance is the charge per volt:
Q = C V
in farads (1 F = 1 C/V).
For parallel plates:
C = ε₀ A / d
Bigger plates, closer together, store more. C does not depend on Q.
The energy stored in a charged capacitor:
U = ½ C V²
Challenge
A capacitor is made of two plates of area 0.02 m², 1 mm apart, and connected to 100 V. How much charge Q does it hold, in nanocoulombs? Work out its capacitance C first, in picofarads.
Try it yourself
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
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