Question

An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is (h = 6.62 x 10^-34 Js, c = 3 x 10⁸ m/s) ____________.

Options

• 5.9 x 10^-4 eV

• 5.9 x 10^-6 eV

• 11.8 x 10^-8 eV

• 11.8 x 10^-6 eV

Answer 1

An important spectral emission line has a wavelength of 21 cm. The corresponding photon energy is (h = 6.62 x 10^-34 Js, c = 3 x 10⁸ m/s) 5.9 x 10^-6 eV.

Explanation:

`"E" ="hc"/lambda`

` = (3 xx 10^8 xx 6.62 xx 10^-34)/(0.21 xx 1.6 xx 10^-19)`

` = 5.9 xx 10^6  "eV"`