Question

A photon of ultraviolet (uv) light possesses enough energy to mutate a strand of human dna. what is the energy of a single uv photon and a mole of uv photons having a wavelength of 25 nm?

Answer 1

Energy of single uv photon= 7.95 x 10⁻¹⁸ J

Energy of a mole of photons=4788213 J

Explanation:

the energy of a photon is given by $E= \frac{h c}{\lambda}$

h= planck's constant=6.626 x 10⁻³⁴ Js

λ= wavelength=25 nm= 25 x 10⁻⁹ m

c= velocity of light= 3 x 10⁸ m/s

so $E= \frac{6.626\times10^{-34}(3\times10^{8})}{25\times10^{-9}}$

E=7.95 x 10⁻¹⁸ J

so energy of one photon=7.95 x 10⁻¹⁸ J

Energy of one mole of photons= 6.022 x 10²³ (7.95 x 10⁻¹⁸ J)

Energy of one mole of photons=4788213 J