Question 1

4 pts

A typical human eye is most sensitive to green light (with a wavelength of 555 nm). One

particular dark-adapted eye has a reliable vision threshold of 6 x10-¹1 W m-2 and a 8.6 mm

diameter pupil. How many photons per second must enter the eye to just barely sustain an

image of a hypothetical star that emits only light with a 550 nm wavelength?

Note: required precision is 1%.

Sanity check: your answer should be between 1000 and 20000