Question

A parallel plate air capacitor has capacitance



c. When it is half filled with a dielectric of dielectric constant 5 the percentage increase and capacitance will be

Answer 1

application of capacity

Answer 2

Answer: 66.67%

Explanation:

The capacitance of parallel plate capacitor is given by

$C = \frac {\epsilon_oA}{d}$

When dielectric is added having width t:

$C' = \frac {\epsilon_oA}{d+t( \frac{1}{\epsilon_r} -1)}$

$\epsilon_r = 5, t = \frac{d}{2}$

Insert the values,

$C' = \frac {\epsilon_oA}{d+d/2( \frac{1}{5} -1)} = \frac{5}{3} C$

Percentage increase in the capacitance when dielectric is added:

$\frac{C'}{C}-1\times 100\%=\frac{5}{3}-1\times 100\% = 66.67\%$