1. The problem statement, all variables and given/known data The wavelength of red light emitted by a 5.00 mW helium-neon laser is 633 nm. If the diameter of the laser beam is 1.60 mm, what is the density of photons in the beam? Assume that the intensity is uniformly distributed across the beam. 2. Relevant equations ??????? 3. The attempt at a solution I do not even know where to start to attempt this problem because I cannot find a formula that looks helpful for this. Any input on what formula I should use or what approach to take would be greatly appreciated.