Question

find the value of frequency velocity and wavenumber of a light wave with wavelength=4200 angstroms

Answer 1

Answer:-

• $\sf \lambda=4200Å$

Frequency:-

$\boxed{\sf v=\dfrac{c}{\lambda}}$

$\\ \sf \longmapsto v=\dfrac{3\times 10^8ms^{-1}}{4200\times 10^{-10}m}$

$\\ \sf \longmapsto v=7.1\times 10^{15}s^{-1}$

$\\ \sf \longmapsto v=7.1\times 10^{15}Hz$

$\\ \underline{\boxed{\bf{\therefore Frequency=7.1\times 10^{15}Hz}}}$

Wavenumber:-

$\boxed{\sf \overline{v}=\dfrac{1}{\lambda}}$

$\\ \sf \longmapsto \overline{v}=\dfrac{1}{4200\times 10^{-10}m}$

$\\ \sf \longmapsto \overline{v}=4200\times 10^{10}m^{-1}$

$\\ \sf \longmapsto \overline{v}=4.2\times 10^{13}m^{-1}$