Electrostatic Potential And Capacitance

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Common Misconceptions

4 min read

Electrostatic Potential And Capacitance

- What you are getting from a statement might not be necessarily true. Let's burst some of the common misconceptions

Can the absolute potential of charged system be calculated?

The absolute potential of a charged system can not be calculated, only we can calculate the potential difference between the points. If we say potential at a point due to any charged system is 'V', its mean that we have already assumed zero potential at any other point.

Can a single conductor also act as a capacitor?

Yes, A single conductor can also act as a capacitor. A capacitor is a device that stores electrical potential energy in the form of electric field. If you consider one spherical conductor then another pair of conductor can be considered with an infinite radius. This arrangement can also store energy in the form of electric potential energy.

Is electric potential energy different from electric field energy?

If you consider charged conducting sphere of radius 'R' and Charge 'Q'. Electric potential energy will be

U = \frac{1}{4 π ϵ _{o}} \frac{Q ^{2}}{R}

. But when you consider Capacitor, it stores energy in form of electric field so this energy is called 'electric field energy' and it is equal to "U=\dfrac12 E^2 \times Volume". There are the two different way of interpretation of same energy. We can regard the energy of a given systam of charges as being shared property of all charges, or we can think of energy as being a property of the electric field that the charges create. Either interpretatiob leads to the same value of the potential energy.

When a capacitor plates with different areas connected are connected with battery. Will the charge on both plates be same?

When two plates of a capacitor having different areas connected with battery the same magnitude of charge will come on both capacitor. Reason behind is that, the battery connected with wire will develop electric field inside the wire this electric field will pull the electron from one plate and the same amount of electron push to the other plate. Hence charge on both will be same.