Question

A parallel plate capacitor with air between the plates has a capacitance c. What will be the capacitance if a) the distance between the plates is doubled? b) the space between the plates is filled with substance of dielectric 5?

Answer 1

Answer:

a)The capacitance becomes C/2 when the distance between the plates is doubled.

b)The capacitance becomes 5C when the space between the plates is filled with substance of dielectric 5.

Explanation:

The capacitance of a parallel plate capacitor is given by,

         $C=k\varepsilon _0\frac{A}{d}$

         Given , k=1

         $C=\frac{\varepsilon _0A}{d}$

a) Given that,

              d'= 2d

              $C'=\frac{\varepsilon _0A}{d'}$

              $C'=\frac{\varepsilon _0A}{2d}=\frac{C}{2}$

b)Given that,

              k = 5

             $C^{\prime}=\frac{5\times \varepsilon _0A}{d}=5C$