Question

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

The correct option is B

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

$E=hv\Rightarrow v=\frac{E}{h}=\frac{1\times {10}^6\times 1.6\times {10}^{-19}}{6.6\times {10}^{-34}}=2.4\times {10}^{20}Hz$