`100` capacitors each having a capacity of `10 muF` are connected in parallel and are charged by a potential difference of `100 kV`. The energy stored in the capacitors and the cost of charging them, if electrical energy costs `108` paise per `kWh`, will be

Options

A. `10^7` and 300 paise
B. `5 xx10^6` and 300 paise
C. `5 xx10^6` and 150 paise
D. `10^7` and 150 paise

Answer

C

Explanation

`C_(eq) = 100 xx10 = 100 muF, V = 100 xx10^3 ` Volt
`U=1/2CV^2 =1/2xx1000 xx10^(-6) xx10^(4) xx10^6`
`= 5 xx10^6 J`
Since, `3.6 xx10^(6) J` cost 108 paise
`:. 5 xx10^6 J` costs `108/(3.6 xx10^6) xx 5 xx10^6 = 150 ` paise