Question

A metal plate is introduces between the plates of a charged parallel plate capacitor. What is its effect on the capacitance of the capacitor

Answer 1

By introducing the metal plate between the plates of charged capacitor, the capacitance of capacitor increases
Reason: It is thickness of metal plate, then
$C=\frac{\epsilon oA}{d-t(1-\frac{1}{k})}$
For metal plate K= $\infty$, $C=\frac{\epsilon oA}{(d-t)}$