Question

Alaser produces red light of wave length 632.8 nm. Calculate the average energy in kJ, of one mole of photons of this red lght

Answer 1

E = hc/wavelength. You know h (or you can look it up), you know c (or can look it up in meters/s), wavelength you know but that must be changed to meters. E will be in J so you will need to convert to kJ. Finally, this is the E for ONE photon of the laser light. Multiply by 6.02E23 to convert to 1 mol photons. Post your work if you get stuck.