What is wavenumber of a radiation having wavelength $0.25 \mu \mathrm{~m}$ ?

What is wavenumber of a radiation having wavelength $0.25 \mu \mathrm{~m}$ ?
  1. $2.5 \times 10^6 \mathrm{~m}^{-1}$
  2. $4.0 \times 10^6 \mathrm{~m}^{-1}$
  3. $6.5 \times 10^6 \mathrm{~m}^{-1}$
  4. $8.0 \times 10^6 \mathrm{~m}^{-1}$

Solution

$\begin{aligned} & \bar{v}=\frac{1}{\lambda} \\ & \frac{1}{0.25 \times 10^{-6} \mathrm{~m}}=4.0 \times 10^6 \mathrm{~m}^{-1}\end{aligned}$

Asked in: MHT CET 2024 (16 May Shift 1)

Practice more Structure of Atom questions on Aicharya