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Energy Stored In A Capacitor Class 12 Physics Electrostatic Potential And Capacitance

Energy Stored In A Capacitor

    We have already studied that capacitors store electrostatic energy in it. Today we will learn how they store energy? and how much energy can be store in a capacitor? As always to find the energy we have to find the work done.

So, consider a small positive charge +dQ, work has to be done to transfer this small +dQ to move towards this positive plate(because it's against the electric field). This work is stored as potential energy.

Work done W = charge X potential i.e, W =qV

Here charge is dQ so we can write

dW = dQ V = dQ Q/C            ( from equation Q = CV )

integrating on both sides we get 

This equation consisted to be general equation. By substituting values of Q and C we get other 2 forms of energy stored in capacitor

   applying Q = CV in equation (1)


applying C = Q/V in equation (1)


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