Explain what would happen if a `3` mm thick mica sheet of (dielectric constant = 6) were inserted between the plates (a) while the voltage supply remained connected (b) after the supply was disconnected.

Explanation

(a) dielectric constant of the mica sheet , k=6
initial capacitance , C=1.771`xx10^(-11)F`
New capacitance , `C'=kC=6xx1.771xx10^(-11) =106 pf`
supply voltage , V=100 V
New charge, q'=C''V `=6xx1.771xx10^(-9) =1.06xx10^(-8) C`
potential across the paltes remain 100 v.
(b) dielectric constant , k=6
initial capacitance, `C=1.771xx10^(-11)F`
New capacitance, C''=kC `=6xx1.771xx10^(-11) =106 pf`
if supply voltage is removed, then there will be no effect on the amount of charge in the plates.
Charge =`1.771xx10^(-9)C`
potential across the plates is given by
`:. V'=q/(C'')`
`=(1.771xx10^(-9))/(106xx10^(-12))`
`=16.7 V`