Question

17.

If a 100-W lightbulb emits 3.5 % of the input energy as visible light (average wavelength 550 nm) uniformly in all directions.

PART A

How many photons per second of visible light will strike the pupil (4.0 mmmm diameter) of the eye of an observer 2.5 mm away?

PART B

How many photons per second of visible light will strike the pupil (4.0 mmmm diameter) of the eye of an observer 1.5 kmkm away?

Answer 1

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