Question
2. Here are two types of lasers: Laser A- 400nm, 10 mW (W=J/s); Laser B- 800 nm, 10 mW.(Assume that hc = 2 x 10-25 J.m) (1) How many photons are included in 1 m of laser beam in each case?Which one has more photons? How many times? (2) When the two lasers irradiate on a metal having the work function of 1 x 10^-19 J,
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