A photographic flash unit consists of a xenon-filled tube. It gives a flash of average power 200 W for 0.04s. The flash is due to discharge of a fully charged capacitor of `40muF`. The voltage to which it is charged before a flash is given by the unit is

Options

A. 1500V
B. 2000V
C. 2500V
D. 3000V

Answer

B

Explanation

`2000xx0.4=(1)/(2)xx40xx10^(-6)V^(2)` or `V^(2)=4xx10^(6) or V=2000V`