InterviewSolution
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InterviewSolution
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Answer» A charged Capacitor is a store of electrical potential energy. To find the energy stored in a capacitor, let us consider a capacitor of capacitance C, with a potential difference V between the plates. There is a charge +q on one plate and –q on the other. Suppose the capacitor is charged gradually. At any stage ,the charge on the capacitor is q. Potential of capacitor =q/C. Small amount of work done in giving an additional charge dq to the capacitor is dW=q/C *dq total work done in giving a charge Q to the capacitor is q. Q=Q W=1/C Q2/2 Energy stored in the capacitor U=W=1/2 Q2/C Put Q=CV U=1/2 (CV)2/C =1/2 CV2 Put CV=Q U=1/2 QV Thus, U=1/2 Q2/C =1/2 CV2=1/2 QV When Q is in coulomb,V is in Volt ,C is in fared .Energy U is in joule. Energy stored in a capacitor is in the form of electric field energy in the charged capacitor and it resides in the dielectric medium between the plates. |
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