Energy of the emitted photon(E) = hcλ
λ = 5.68 x 10−6m
h = 6.63 x 10−34Js
c = 3.0 x 108ms−1
E =(6.63×10−34)×(3.0x108)5.68×10−6 = 1.989×10−255.68×10−6
E = 3.50 x 10−20J
Therefore, the energy change = 3.50 x 10−20J
