Some small, bright lightbulbs on a strand (Fig. Q25.13) are grouped in pairs according to color and then spaced 5 cm apart.
(a) From a long distance, it becomes difficult to tell if each color is coming from one bulb or from a pair. Why?
(b) There is a distance from the lights where the pairs of blue bulbs can be resolved but the pairs of red bulbs would look like one point. What feature of the red and blue light would account for this difference?