Question

What happens to the potential difference between the plates of a capacitor as the thickness of the dielectric slab increases?

(a) Increases

(b) Decreases

(c) Remains the same

(d) Becomes zero

This question was addressed to me in a job interview.

Enquiry is from Composite Dielectric Capacitor in division Capacitance and Capacitors of Basic Electrical Engineering

Answer 1

The correct answer is (b) Decreases

Explanation: When a dielectric is introduced between the plates of a capacitor, its potential difference decreases.

New potential difference= potential difference without dielectric-potential difference of dielectric. Hence as the thickness of the dielectric slab increases, a larger value is subtracted from the original potential difference.