Question

The wave number of the radiation whose quantum $1$ erg is:

• A. $5\times {10}^{15}c{m}^{-1}$
• B. $15\times {10}^{5}c{m}^{-1}$
• C. $1.5\times {10}^{15}c{m}^{-1}$
• D. $5\times {10}^{5}c{m}^{-1}$

Answer 1

The correct option is A $5\times {10}^{15}c{m}^{-1}$

$Energy=1erg$

$\frac{hc}{\lambda }=1erg$ $\frac{1}{\lambda }=wavenumber$

$\frac{1}{\lambda }=\frac{1}{hc}$

$\overline{u}=\frac{1}{hc}$

$\overline{u}=\frac{1}{6.626\times {10}^{-27}\times 3\times {10}^{10}}$

$\overline{u}=\frac{100}{19.878}\times {10}^{15}=5.03\times {10}^{15}c{m}^{-1}$