Nitrogen laser produces a radiation at a wavelength of 337.1 nm. If the number of photons emitted is 5.6 × 1024, calculate the power of this laser.

The power of the laser is,
E = Nhc/λ
where
E = power of the laser
N = No of photons = 5.6 × 1024
h = Planks constant = 6.626 × 10-34 Js
c = speed of light = 3.0 × 108 m/s
λ = wavelength = 337.1 × 10-9 m
E = (5.6 × 1024 × 6.62 × 10-34 × 3 × 108) / (337.1 × 10-9)
= 3.3 × 106 J/s
= 3.3 × 106 W