Question

If a source of power 4 kW produces ${10}^{20}$ photon/second, the radiation belong to a part of the spectrum called, (h=$6.6\times {10}^{-34}$Js )

• A. x-rays
• B. UV-rays
• C. microwaves
• D. gamma-rays

Answer 1

The correct option is A x-rays

power $=\frac{nhv}{t}P=\left(\frac{n}{t}\right)hv\Rightarrow 4\times {10}^3={10}^{20}\times 6.6\times {10}^{-34}\times v\Rightarrow v=\frac{4\times {10}^3}{6.6\times {10}^{-14}}=6\times {10}^{16}Hz$
The obtained frequency lies in the band of X-rays