Question

Electromagnetic radiation of wavelength 242 nm is just sufficient to ionize the sodium atom. What is the ionization energy of sodium per atom?

• A. $494.5\times {10}^{-6}J/atom$
• B. $3169.5\times {10}^{-10}J/atom$
• C. $5.85\times {10}^{-15}J/atom$
• D. $8.214\times {10}^{-19}J/atom$

Answer 1

The correct option is D $8.214\times {10}^{-19}J/atom$

Energy=$\frac{hc}{\lambda }=\left(\frac{6.63\times {10}^{-34}\times 3\times {10}^6}{}\right)$joule

$=0.08219\times {10}^{-17}$joule/atom

$\therefore$ $=8.219\times {10}^{-19}$j/atom

$\approx 8.214\times {10}^{-19}$j/atom