Question

How many photons are produced in a laser pulse of 0.819 J at 531 nm?

Answer 1

find the energy given by one photon of that wavelength

E=hc/lambda

divide the energy given 0.819 J by the energy of one photon

Answer 2

\[3.74 \times 10^-37\]?

Answer 3

what energy did you get per photon

Answer 4

0.000000000374 = 3.74*10^-10 J /photon

Answer 5

Divide that that by .819?

Answer 6

the other way around

0.819 J/3.74*10^-10 J = # of photons

Answer 7

Ah.\[2.19\times10^9\]

Answer 8

that sounds right