Question

One plate of parallel plate capacitor is smaller than the other. The charge on the smaller plate:

• A. will be less than other
• B. will be more than other
• C. will be equal to other
• D. will depend upon the medium between the plates

Answer 1

The correct option is C will be equal to other

Let us take the above shown Gaussian surface.
We know that inside the conductors, $E=0$
$\therefore \varphi =0$

So the net enclosed charge must be zero.
$\therefore$ the charge on the other plate must be equal in magnitude and opposite in sign regardless the shape of other plate.