posted by J .
A laser used to weld detached retinas emits light with a wavelength of 652 nm in pulses that are 20 ms in duration. THe average power expended during each pulse is .600 W. (a) How much energy is in each pulse, in joules and electron volts? (b) What is the energy of one photon in joules and electron volts? (c) How many photons are in each pulse?
ok, I know how to get the electronvolts once I get the joules...but I can't figure out the joules! Help please!