Answer to Question #114355 in General Chemistry for Samuel

Question

One type of sunburn occurs on exposure to UV light of wavelength in the vicinity of 305 nm. How many photons are in 1.15mJ burst of this radiation?

Answer 1

$E=ch/\lambda$ E - photon energy, с - speed of light (3*10⁸m/s), $\lambda$ - wavelength, h - Planck's constant (6,23*10^-34kg*m²/s)

E=3*10⁸m/s*6,23*10^-34kg*m2/s/305*10^-9m=6,12*10^-19J

Whole E=0,00115J

N - photons ammount

N=0,00115J/6,12*10^-19J=1,88*10¹⁵ photons

Answer:1,88*10¹⁵ photons