In a parallel plate condenser, the radius of each circular plate is `12 cm` and the distance between the plates is `5mm`. There is a glass slab of `3 mm` thick and of radius `12 cm` with dielectric constant `6` between its plates. The capacity of the condenser will be

Options

A. `144 xx 10^(-9) F`
B. `40pF`
C. `160 pF`
D. `1.44 muF`

Answer

C

Explanation

`C = (epsilon_(0)A)/(d-t + (t)/(K)) = (1)/(4 pi xx 9 xx 10^(9)).(pi(0.12)^(2))/((2+(1)/(2))10^(-3))`
`= (2 xx 144 xx 10^(-10))/(36 xx 5) = 160 pF`