Most of the ultraviolet radiation reaching the surface of the earth is UV-A radiation, which has a wavelength range of 315 nm to 400 nm.

Question

UV-A radiation is a cause of skin aging and also contributes to development of skin cancer. Determine the energy of a mole of photons of UV-A radiation that have a wavelength of 325 nm

Answer 1

Most of the ultraviolet radiation reaching the surface of the earth is UV-A radiation, which has a wavelength range of 315 nm to 400 nm.

UV-A radiation is a cause of skin aging and also contributes to development of skin cancer. Determine the energy of a mole of photons of UV-A radiation that have a wavelength of 325 nm

Hello Mikayla,

Use equation: E = c*h / λ where,

E = energy in Joules

c = Speed of light = 3.0x10⁸ m/s

h = Planck's constant = 6.626x10^-34 J*s

λ = Lambda is the wavelength in meters : 325nm * 1m / 10⁹ nm = 3.25 x 10^-7 m

E = (3.0 x 10⁸ m/s)*(6.626 x 10^-34 J*s) / 3.25 x 10^-7 m = 6.12 x 10^-19 J (per photon)

Multiply by 6.02x10²³ to get the total energy for 1 mole of photons:

6.12 x 10^-19 J/photon * 6.02 x 10²³ photons/mol = 368,201 J

Answer: The energy of 1 mole of UV-A photon radiation is equivalent to 368,201 J or 368.2 kJ