A 600 W mercury lamp emits monochromatic rediation of wavelength 331.3 nm. How many photons are emitted from the lamp per second? `(h = 6.626xx 10^(-34)` Js, velocity oflight= `3xx 10^(8) ms^(-1))`

Options

A. `1xx10^(39)`
B. `1xx10^(20)`
C. `1xx10^(21)`
D. `1xx10^(23)`

Answer

C

Explanation

Energy of a photon, `E=(he)/(lamda)`
`=6.626xx10^(-34) (Js)xx3xx10^(8)(ms^(-1))/(331.3xx10^(-9)(m))=6xx10^(-19)J`
No. of photons emitted per second
`=(600(J))/(6xx10^(-19)(J))=10^(21)`