Figure shows the stopping potential versus the light frequency for a metal cathode used in a photoelectric-effect experiment. Suppose this cathode is now illuminated with `6.63 mu`W of 300 nm light and that the efficiency of converting photons to photoelectrons is 10% Take `h=6.63xx10^(-34)` Jsec,`c=3xx10^(8)ms^(-1)`
What is the power (in watt) of emitted photoelectron beam assuming that on an average, each photoelectron emitted has energy `(5K_(max))/6` Assume that anode potential is sufficiently positive. Express your answer in from of `'X' xx 10^(-9)` W fill 'X' in OMR sheet after rounding off to nearest integer.

Answer

`0221`

Explanation

`(dN)/(dt)=(P_(0)xxlambda)/(hC)xxeta=0.1xx(6.63xx10^(-6)xx300xx10^(-9))/(6.63xx10^(-34)xx3xx10^(8))=10^(12) sec^(-1)`
`E=h(f-f_(T))`
`P=5/6xxExx10^(12)=221xx10^(-9)`W