# Chapter 4 Early Quantum Theory - Problems: 24

E = hc/ λ = (6.626 x 10$^{-34}$) (3 x 10$^{8}$) / 193 x 10$^{-9}$ = 0.103 x 10$^{-17}$ J Energy delivered = No. of Photons x Energy of 1 Photon = 2.5 x 10$^{16}$ x 0.103 x 10$^{-17}$ = 26 mJ