Question

The wavelength of a $1$keV photon is $1.24\times {10}^{-9}$m. What is the frequency of $1MeV$ photon?

• A. $1.24\times {10}^{15}Hz$
• B. $2.4\times {10}^{20}Hz$
• C. $1.24\times {10}^{18}Hz$
• D. $2.4\times {10}^{23}Hz$

Answer 1

Answer: (B)

$2.4\times {10}^{20}Hz$

Here, $\frac{hc}{\lambda }={10}^{3}eV$ and $hv={10}^{6}eV$

Hence, $v=\frac{{10}^{3}c}{\lambda }=\frac{{10}^3\times 3\times {10}^8}{1.24\times {10}^{-9}}$

$=2.4\times {10}^{20}Hz$