`A 40 muF` capacitor in a defibrillator is charged to `3000 V`. The energy stored in the capacitor is sent through the patient during a pulse of duration `2 ms`. The power delivered to the patient is

Options

A. `45 kW`
B. `180 kW`
C. `90 kW`
D. `360 kW`

Answer

C

Explanation

A capacitor is a device that stores energy in the electric field between a pair of conductors on which equal but opposite electric charges have been placed.
The energy stored in a capacitor `= (1)/(2)CV^(2)`
Given, `C = 40muF = 40 xx 10^(-6)F, V = 3000 V`
`:. E = (1)/(2) xx 40 xx 10^(-6) xx (3000)^(2) = 180 J`
Also `1W = 1 J//s :. 2ms = 2 xx 10^(-3) s`
Hence, power `= (180 J)/(2 xx 10^(-3) s)`
`= 90 xx 10^(3) W = 90 kW`