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

Options

A. decreases
B. remains unchanged
C. becomes infinite
D. increases

Answer

B

Explanation

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.
Alternate method:
From the formula `C=(epsi_(0)A)/(d-t+(t)/(K))`
Here, `K=oo and t to 0` So, `C=(epsi_(0)A)/(d+0)=(epsi_(0)A)/(d)=C_(0)`.