Which of the following phenomena is a function of the distribution of the rods and cones in the retina?
A) Stars can be seen only with difficulty during the daytime.
B) A dim star may disappear when you look directly at it but reappear when you look to one side of it.
C) The light from distant stars moving rapidly away from us is shifted toward the red end of the spectrum.
D) The moon looks much larger near the horizon than it looks when it is higher in the sky.

Question

Quizplus · Accepted Answer

This phenomenon, known as "the Purkinje shift," is the result of the distribution of rods and cones in the retina. Rods are more sensitive to light and are concentrated in the fovea, the center of the retina. Cones are responsible for color vision and are more densely packed towards the periphery of the retina. When you look directly at a dim star, the light is being focused on the fovea where there are fewer cones to detect it, so it appears dimmer or may even disappear altogether. When you look to one side of the star, the light is being detected by more cones, so it may become more visible.

Which of the Following Phenomena Is a Function of the Distribution