Question

Things around you are emitting infrared radiation that includes the wavelength 9.9 x 10⁻⁶m. What is the energy of these IR photons?

(Unrelated answers will be reported. Thank you.)

Answer 1

Given:-

wavelength of IR radiation, $\lambda=9.9\times10^{-6}m$

To Find:-

Energy of these photons

Explanation:-

$\text{According to Planck's law of radiation, Energy of the photons is given by the formula:-}\\\\E=\dfrac{hc}{\lambda}\text{ where,}\\\\ h=\text{planck's constant}=6.626\times10^{-34}J-s\\\\c=\text{velocity of light}=3\times10^{8}m/s\\\\\Rightarrow\text{Energy, E}=\dfrac{6.626\times10^{-34}\times3\times10^{8}}{9.9\times10^{-6}}=2\times10^{-20}J$

Answer 2

As the things around are emitting infrared radiations

Find- We have to find the Energy of the IR photons

Explanation:

Given:-

The wavelength that is  λ =$9.9\times10^{-6} m$

we know by the formula for energy is

$E=\frac{hc}{λ}$

where h is the Planck's constant having a value $6.626\times10^{-34} J-sec$

c is the speed of light =$3.8\times10^{8} m/sec$

and λ is the wavelength

so,

$E=\frac{{6.626\times10^{-34}\times3\times10^{8}}}{9.9\times10^{-6} }\\E=2.001\times10^{-20}$

Dividing Energy by charge of an electron to find the energy of these IR photons

$\frac{2.001\times10^{-20} }{1.6\times10^{-19} } \\=0.125 eV$

Hence, the energy of these IR photons is 0.125eV