Question

If the source of power $4kwW$ produces ${10}^{2}0$ photons/second, the radiation belongs to the part of a spectrum called

• A. X rays
• B. Ultraviolet rays
• C. Microwaves
• D. Gamma rays

Answer 1

The correct option is B Ultraviolet rays

$E=4kw=nh\nu$

$\nu =\frac{4\times {10}^3}{n\ast h}$

$\nu =\frac{4\times {10}^3}{{10}^{20}\ast 6.62\ast {10}^{-34}}$

$\nu =6.0368\times {10}^{16}Hz$

We know this is belongs to frequency range of ultraviolet spectrum.

Hence option 'B' is correct.