Question

How many photons are produced in a laser pulse of 0.372 J at 471 nm?

Answer 1

The relationship between energy of a single photon and its wavelength can be determined using the formula E=hc/lambda where h is Planck's constant, c is the speed of light, and lambda is the wavelength in units of meters. If we can find the energy of a single wavelength of 471 nm, we can then determine the number of photons that total 0.372 J.

Before we can solve for the energy, we need to convert 471 nm to meters.

471 nm (1 m / 1 x 10⁹ nm) = 4.71 x 10^-7 m

Then, we can plug in the values we know into the equation

E = (6.63 x 10^-34 Js)(3 x 10⁸ m/s) / 4.71 x 10^-7 m

E = 4.22 x 10^-19 J

This gives us the energy in Joules of a single photon. Now, we can find the number of photons in 0.372 J

0.372 J / 4.22 x 10^-19 J = 8.81 x 10¹⁷ photons