An air-traffic controller is trying to spot the lights of an airplane on the horizon at night. He should look
A)directly where he thinks it is.
B)with one eye only.
C)next to where he thinks it is.
D)at a bright light to preadapt his eyes.

Question

Quizplus · Accepted Answer

The human eye is more sensitive to dim light in the periphery of the visual field than directly in the center. This is due to the distribution of rods and cones in the retina, with rods (more sensitive in low light) being more prevalent in the peripheral areas. Therefore, looking slightly off to the side of where one expects to see a dim light, such as an airplane's lights at night, can make it easier to spot.

An Air-Traffic Controller Is Trying to Spot the Lights of an Airplane