Question

The warming of the thermosphere (the upper level of the atmosphere) is caused by the photo absorption of high energy photons. One of the processes that occurs in the thermosphere is the photo ionization of N2(g). N2(g) + hν → N2+(g) + e− What is the maximum wavelength of a photon needed to ionize N2 if the ionization energy of N2 is 1495 kJ/mol? In what region of the electromagnetic spectrum does a photon of this energy belong?

Answer 1

Answer:

Wavelength of photon is 80.1 nm and it belongs to UV region.

Explanation:

If wavelength of required photon is $\lambda$ then-

                                 $N_{A}\frac{hc}{\lambda }=1495kJ$

where, $N_{A}$ is avogadro constant, h is plank constant, c is velocity of light.

So, $(6.023\times 10^{23})\times \frac{6.626\times 10^{-34}J.s\times 3\times 10^{8}m.s^{-1}}{\lambda }=1495\times 10^{3}J$

or, $\lambda$ = $8.01\times 10^{-8}m$

or, $\lambda$ = 80.1 nm

As wavelength of photon lies between 1-100 nm therefore the photon belongs to UV region of electromagnetic spectrum.