A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

Question

A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor (A) decreases (B) remains unchanged (C) becomes infinite (D) in creases

Tardigrade Admin · Accepted Answer

Aluminium is a metal, so when we insert an aluminium foil, equal and opposite charges appear on its two surfaces. Since, it is of negligible thickness, it will not affect the capacitance. Alternative From the formula

C = \frac{ε _{0} A}{d - t + \frac{t}{K}}

Here,

K = \infty

and

t \to 0

So,

C = \frac{ε _{0} A}{d + 0} = \frac{ε _{0} A}{d} = C_{0}

Q. A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

decreases

remains unchanged

becomes infinite

in creases