Q. The wavelength of a 1 keV photon is 1.24 nm. The frequency of 1 MeV photon is
A) $1.24 \times 10^{15}$Hz
B) $2.4 \times 10^{20}$ Hz
C) $1.24 \times 10^{18}$ Hz
D) $2.4 \times 10^{24}$ Hz
Explanation
(b) $f = \frac{c}{\lambda} = \frac{c}{hc/E}$=$\frac{E}{h}$
$\therefore\ \ \ \ \ \ \ \ \ f = \frac{1 \times 1.6 \times 10^{- 13}}{6.6 \times 10^{- 34}} = 2.4 \times 10^{20}$Hz
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.