Question

A 100pF capacitor is charged to a potential difference of 24V.It is connected to a uncharged capacitor of capacitance 20pF.What will be the new potential difference accross the 100pF capacitor?

Answer 1

Answer:

The new potential difference across the 100 pF capacitor is 20 volt.

Explanation:

Given that,

Capacitor C = 100pF

Potential difference V = 24 volt

Uncharged capacitor C' = 20pF

The charge on the capacitor

$q = C\times V$

$q = 100\times24$

$q = 2400\ pC$

Let us consider q charge flows from one capacitor to another capacitor.

The charge will stop flowing when the potential becomes equal across both the capacitors.

$\dfrac{2400-q}{100}=\dfrac{q}{20}$

$2400\times20-20 q=100q$

$q = 400\ pC$

So, The new potential will be

$V = \dfrac{q}{C}$

$V= \dfrac{400}{20}$

$V = 20\ volt$

Hence, The new potential difference across the 100pF capacitor is 20 volt.