hen the eye sees a star (a point of light), the pupil spreads by diffraction the image of the star to a small round spot on the retina. suppose the light from the star has a wavelength of m. when the pupil is at its largest, it may have a diameter of 7.0 mm. a) if the distance from the pupil to the retina is 23 mm, what then is the diameter of the image of the star on the retina? in the middle of retina, there are approx. 150,000 light-sensitive cells per . b) how many of these cells are illuminated when the eye looks at the star?
