physics
posted by rick .
A laser emits 1.44*10^18 photons per second in a beam of light that has a diameter of 1.98 mm and a wavelength of 524.5 nm.
(a) Determine the average electric field strength
(b) Determine the average magnetic field strength for the electromagnetic wave that constitutes the beam.

You know the energy (given wavelenght and the number of photons)
http://en.wikipedia.org/wiki/Poynting_vector
You know the Poynting vector (watts/m^2) in the beam, so figure E and B.
check my thinking. 
still don't understand where does wavelength and number of photons go too? do you divdide them to get energy or what?

You get energy per photon from Planck's equation, then multiply by the nubmer to get joules/second (watts).