Answer:
[tex]\frac{n}{t} = 30\ photons/s[/tex]
Explanation:
The radiated power can be given in terms of the wavelength as follows:
[tex]Rasiated\ Power = \frac{nE}{t} = \frac{nhc}{\lambda t}[/tex]
where,
Radiated Power = 1.2 x 10⁻¹⁷ W
n = no. of photons = ?
h = plank's constant = 6.625 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength = 500 nm = 5 x 10⁻⁷ m
t = time
Therefore,
[tex]1.2\ x\ 10^{-17}\ W = \frac{n(6.625\ x\ 10^{-34}\ J.s)(3\ x\ 10^8\ m/s)}{(5\ x\ 10^{-7}\ m)(t) }\\\\\frac{n}{t} = \frac{1.2\ x\ 10^{-17}\ W}{3.975\ x\ 10^{-19}\ J}\\\\\frac{n}{t} = 30\ photons/s[/tex]
