Question

How many photons are produced in a laser pulse of 0.379 J at 463 nm?

Answer 1

To answer this you need to know the formula for the energy of a photon of given wavelength, which is\[\epsilon=\frac{ hc }{ \lambda }\]
where h is Planck's constant, c is the speed of light and lambda is the wavelength.
Just divide the energy in the pulse by the energy of a single photon to get your answer.