A monochromatic source of light operating at 500W emits `6xx10^(20)` photon per second. Find the wavelength of the light used. Use `h=6.6xx10^(-34)Js , C=3xx10^8m//s`

Explanation

Power, P=500W No. of photons
emitted per second, `n=6xx10^(20)`
Let `lambda` be the wavelength of light emitted by the source. Then energy of photon emitted=`(hc)/lambda` Energy of all the photons emitted per second will be `P=nxx(hc)/lambda`
or `lambda=(nhc)/P`
`=((6xx10^920)xx(6.6xx10^(-34))xx(3xx10^8))/500`
`=23.76xx10^-8m`
`=2376xx10^(-10)m=2376Å`