Question

Which among the following is the correct expression for force between the plates of a parallel plate capacitor?

(a) F=epsilon*A*(V/x)^2/2

(b) F=epsilon*A*(V/x)^2/3

(c) F=epsilon (V/x)^2/2

(d) F=epsilon (V/x)^2/3

I had been asked this question in exam.

This intriguing question originated from Force of Attraction Between Oppositely Charged Plates topic in portion Capacitance and Capacitors of Basic Electrical Engineering

Answer 1

Right option is (a) F=epsilon*A*(V/x)^2/2

The best explanation: The force is proportional to the square of the potential gradient and the area. Hence the force F=epsilon*A*(V/x)^2/2.