Condenser `A` has a capacity of `15 muF` when it is filled with a medium of dielectric constant `1.5`. Another condenser `B` has a capacity `1muF` with air between the plates. Both are charged separately by a battery of `100V`. After charging, both are connected in parallel without the battery and the dielectric material being removed. The common potential now is

Options

A. `400 V`
B. `800 V`
C. `1200 V`
D. `1600 V`

Answer

B

Explanation

charge on first capacitor
`=15 muF xx 100V = 1500 muC`
charge on second capacitor
`= 1muF xx 100V = 100muC`
After remive of dielectric medium. It's capacitor

common potential
`= ("Total charge")/("Total capacity") = (1500+100)/(1+1) = 800V`