Small helium-neon lasers emit 3.49mJ/s of light at 634nm. How many photons does such a laser emit in one minute. Any help in solving this question is greatly appreciated :)
I'm not too sure what formula to use and moreover how to solve the question...
I'm not too sure what formula to use and moreover how to solve the question...
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Energy = (h * c) ÷ λ
h = 6.63 * 10^-34 J * s
c = 3 * 10^8 m/s
λ = 634 nm = 634 * 10^-9 m
Energy = (6.63 * 10^-34 * 3 * 10^8) ÷ 634 * 10^-9
Energy of one photon = 3.14 * 10^-19 J
Power = Energy ÷ time
3.49 * 10^-3 Joule/second ÷ 3.14 * 10^-19 Joules/photon = 1.11 * 10^16 photons/second
h = 6.63 * 10^-34 J * s
c = 3 * 10^8 m/s
λ = 634 nm = 634 * 10^-9 m
Energy = (6.63 * 10^-34 * 3 * 10^8) ÷ 634 * 10^-9
Energy of one photon = 3.14 * 10^-19 J
Power = Energy ÷ time
3.49 * 10^-3 Joule/second ÷ 3.14 * 10^-19 Joules/photon = 1.11 * 10^16 photons/second