P133a Problem Set 7

Due at the beginning of class on FRIDAY, May 22, 1998.

Chapter 40: 6, 9, 15, 21, 30, 32, 54,

8. Suppose that a 100W source radiates light of wavelength 600nm in all directions and that the eye can detect this light if only 20 photons per second enter a dark adapted eye having a 7mm diameter pupil. How far from the source can the light be detected under these extreme conditions?