Question 292: Electrostats & Capacitance

Question

A parallel plate capacitor of capacitance 90 pF is connected to a battery of emf 20 V. If a dielectric material
of dielectric constant K = 5/3 is inserted between the plates, the magnitude of the induced charge will be :

Accepted Answer

Charge on Capacitor initially,
Q
i
= CV
After inserting dielectric of dielectric constant = K,
new capacitance, Q
f
= (KC) $$ \vee $$
$$	herefore\,\,\,$$ Induced charges on dielectric
= Q
f
$$-$$ Q
i
= KCV $$-$$ CV
= (K $$-$$ ) CV
= $$\left( {{5 \over 3} - 1} ight)$$ $$ 	imes $$ 90 $$ 	imes $$ 10
$$-$$12
$$ 	imes $$ 20
= 1.2 $$ 	imes $$ 10
$$-$$9
C
= 1.2 nC

Answer

0.9 n C

Answer

1.2 n C

Answer

0.3 n C

Answer

2.4 n C

Electrostats & Capacitance

A parallel plate capacitor of capacitance 90 pF is connected to a battery of emf 20 V. If a dielectric material of dielectric constant K = 5/3 is inserted between the plates, the magnitude of the induced charge will be :

Choose the correct answer: