Question

What will be the wavenumber of yellow radiation having wavelength $240\,nm$?

• A. $1.724 \times 10^4\, cm^{-1}$
• B. $4.16 \times 10^6\, cm^{-1}$
• C. $4 \times 10^{14}\, Hz$
• D. $219.3 \times 10^3\, cm^{-1}$

Answer 1

Answer: (B)

Wavelength of yellow light $= 240 \,nm$
$= 240 \times 10^{-9}\, m$
Wavenumber $\left(\bar{\upsilon}\right)=\frac{1}{\lambda}$
$=\frac{1}{240 \times 10^{-9}\,m}$
$=4.16 \times 10^{6}\,m^{-1}$