Answer:
425 nm
Step-by-step explanation:
If 1 mol = 6.02 * 10^23
The energy (E)= 282 * 10^3/6.02 * 10^23 = 4.684 * 10^-19 J
Now;
E = hc/λ
h = Plank's constant = 6.63 * 10^-34 Js
c = speed of light= 3 * 10^8 m/s
λ = Wavelength of light = ?
4.684 * 10^-19 = 6.63 * 10^-34 * 3 * 10^8/λ
λ = 6.63 * 10^-34 * 3 * 10^8/4.684 * 10^-19
λ = 4.25 * 10^-7 m
λ = 425 * 10^-9 m
λ = 425 nm