ECE532 Biomedical Optics
© 1998 Steven L. Jacques, Scott A. Prahl
Oregon Graduate Institute

EXAMPLE: Intensity of a flashlight

A cheap flashlight projects a beam that is 200 mW to create a 10-cm-diameter spot on a wall 25 cm meters away. The face of the flashlight has a 3-cm diameter. What is the radiant intensity of beam?

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