6.1.2 Energy

• Work is done to remove electrons from the positive plate and deposit them on the negative plate as like charges repel and opposites attract.
• Graphically:

  We can plot a graph of Charge, Q against Voltage, V we get a straight line through the origin

  Gradient = Capacitance

  Energy stored in the capacitor = Work done charging the capacitor
• Equations:

  Area = 1/2 Q *V

  This is because half the energy is dissipated as heat in the resistance of the pathway
• W = 1/2 Q*V

  Substituting Q for CV: W = 1/2 C*V*V

  Substituting V for Q/C = W = 1/2 Q*Q/C
• Uses of capacitors:

  Smoothing capacitors, and Camera Flashes