Question

Find the equivalent capacitance between terminals ‘P’ and ‘Q’, where A is area of plates, ‘d’ is the distance between the two plates and K is the electric constant.

Answer 1

Given:

2 parallel plates of area A and d distance apart are placed between 2 terminals P and Q.

K is electric constant.

To Find:

Equivalent capacitance

Solution:

Capacitance of a body is defined as the charge storing capacity of a body.

Its SI unit is farad.

It is also defined as the ratio of charge in columbs and voltage in volts.

The capacitance of a parallel plate capacitor depends on the area of the plates A and their distance of  separation d. According to Gauss's law, the electric field between the two plates is equal to:

$E = \frac{Q}{\epsilon_{0} A} \\\Ed = V = \frac{Qd}{\epsilon_{0} A}$

Since

$V = \frac{Q}{C} \\C = \frac{\epsilon_{0} A }{d}$

The equivalent capacitance between terminal P and Q is $C = \frac{\epsilon_{0} A }{d}$ .