If a 100-W lightbulb emits 3.0% of the input energy as
Chapter 27, Problem 74(choose chapter or problem)
If a 100-W lightbulb emits 3.0% of the input energy as visible light (average wavelength 550 nm) uniformly in all directions, estimate how many photons per second of visible light will strike the pupil (4.0 mm diameter) of the eye of an observer, (a) 1.0 m away, (b) 1.0 km away.
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