If a source of power `4 kW` produces `10^(20)` photons`//`second, the radiation belongs to a part of the spectrum called:

Options

A. `gamma`-rays
B. X-rays
C. Ultraviolet rays
D. Microwaves

Answer

B

Explanation

Power of the source `=4kW=4xx10^(3)W`
But Power `=("Work")/(t)=("Energy")/("Time")`
But`E=hv` and for n photons, `E=nhv`
`:.P=(nhv)/(t)=Nhv" "` where `N=n/t=`no. of photons emitted/sec
`:.P=(Nhc)/(lambda)( :'v=c/lambda)`
`:.lambda=(Nhc)/(P)=(10^(20)xx6.63xx10^(-34)xx3xx10^(8))/(4xx10^(3))`
`=5xx10^(-9)m=50xx10^(-10)=50Å`
Thus this wavelength lies in the X-ray region.