Question

Calculate the number of photons, from green light of mercury (ʎ = 4961 Å), required to do one joule of work.

(a) 4524.2×10^18/m^3

(b) 2.4961×10^18/m^3

(c) 2.4961/m^3

(d) 2.4961/m

The question was asked in my homework.

I want to ask this question from Laser in section Laser of Engineering Physics II

Answer 1

Correct option is (b) 2.4961×10^18/m^3

The best explanation: E = hc/ʎ

E = 4.006×10^-19 Joules

Number of photons required = (1 Joule)/(4.006×10^-19)

N = 2.4961×10^18/m^3.