Question

UVC light used in sterilizers, has wavelengths between 100 to 280 nm. If a certain UVC wave has a wavelength of 142.9 nm, what is the energy of one of its photons in J

Answer 1

The energy of one of its photons is 1.391 x 10⁻¹⁸ J

Step-by-step explanation:

Given;

wavelength of the UVC light, λ = 142.9 nm = 142.9 x 10⁻⁹ m

The energy of one photon of the UVC light is given by;

E = hf

where;

h is Planck's constant = 6.626 x 10⁻³⁴ J/s

f is frequency of the light

f = c / λ

where;

c is speed of light = 3 x 10⁸ m/s

λ is wavelength

substitute in the value of f into the main equation;

E = hf

`E = (hc)/(\lambda) \\\\E = (6.626*10^(-34) *3*10^(8))/(142.9*10^(-9)) \\\\E = 1.391*10^(-18) \ J`

Therefore, the energy of one of its photons is 1.391 x 10⁻¹⁸ J