Question

. A parallel plate capacitor has a capacitance of 50 p F in air and 150 p F when immersed in oil. The dielectric constant of oil is -------

Answer 1

Answer:

Dielectric of oil is 3

Explanation:

Capacitance of parallel plate capacitor under normal conditions

$C_{1} = \frac{E_{0}A }{d} = 50$

When the capacitor is immersed in oil, capacitance changes as:

$C = \frac{E A}{d}$                      , E is dielectric of oil

$C_{2} = \frac{E_{o} E_{r} A}{d}= 150$                  , $E = E_{0} E_{r}$

$\frac{C_{1} }{C_{2} } = \frac{1}{E_{r} } = \frac{50}{150}$

$E_{r} = 3$