Capacitance | What Is Capacitance

 

Capacitance | What Is Capacitance :- The ability of a conductor to store electric charge is called capacitance.

The potential of a conductor is directly proportional to the charge given to it, i.e.,

V ∝ Q

or

Q ∝ V

⇒ Q = CV

Here, C is a proportionality constant, which is called the capacitance of the conductor.

C = Q/V     …..(1)

Therefore, the capacitance of a conductor is equal to the ratio of the charge given to it to the potential difference produced.

The slope of the graph between charge and potential difference is equal to the capacitance of the conductor; therefore,

 

Capacitance Units

(Capacitance | What Is Capacitance)

(i) The SI unit of capacitance is farad.

Coulomb/Volt = Farad

In equation (1), if Q = 1 coulomb and V = 1 volt, then , therefore

A conductor has a capacitance of 1 farad if, on giving it a charge of 1 coulomb, the potential difference of the conductor becomes 1 volt.

(ii) C.G.S. unit of capacitance is stat farad.

Other smaller units of capacitance :-

 

Dimensions of Capacitance

(Capacitance | What Is Capacitance)

C = Q/V = Q/(W/Q) = Q²/W

⇒ [C] = [A²T²] / [M¹L²T^-2] = [M^–1 L^–2 T⁴ A²]

The capacitance of a conductor does not depend on the charge given to it or on its potential, nor does it depend on the material of the conductor. It depends only on the geometrical configuration of the conductor (its size, shape, and separation) and on the surrounding medium.