Question

A single capacitor is charged up and then isolated with potential V0. A dielectric, κ = 3, is placed
between its two plates, which of the following terms are correct for this ‘new’ capacitor (pick more
than one)

a. C = 1/3 C0 b. C = 3 C0 c. V = 1/3 V0 d. V = 3 V0

e. Q = 1/3 Q0 f. Q = 3Q0 g. E = 1/3 E0 h. E = 3 E0

Answer 1

Answer:

option (b), (c), (g)

Explanation:

When the battery is disconnected, the charge on the plates of a capacitor remains same.

As the capacitance of the capacitor is directly proportional to the dielectric constant.

C = k C0

Now the charge remains same, So

Q = Q0

Q = k C0 x V0 / k

So, potential between the plates is V0 / k.

Energy, E = 1/2 x C X V^2 = 1/2 x k C0 x V0^2 / k^2 = E0 / k

So, energy becomes E0 / k.