Q. The wavelength of $K_{\alpha}$ line in copper is $1.54\ \mathring{\mathrm{A}}.$ The ionization energy of $K$ electron in copper in $Joule$ is
A) $11.2 \times 10^{- 27}$
B) $12.9 \times 10^{- 16}$
C) $1.7 \times 10^{- 15}$
D) $10 \times 10^{- 16}$
Explanation
(b) Required ionisation energy
$= \frac{hc}{\lambda} = \frac{6.6 \times 10^{- 34} \times 3 \times 10^{8}}{1.54 \times 10^{- 10}}J = 12.9 \times 10^{- 16}J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.