If the first light is exactly twice as bright as the second light physically,how will it appear?

Question

Quizplus · Accepted Answer

The perception of brightness is not linearly related to the physical intensity of light. According to Weber's Law, the perceived difference between two stimuli is proportional to the magnitude of the stimuli. Since the first light is only twice as bright physically, it will not appear to be twice as bright to our eyes. It will be perceived as only slightly brighter than the second light, but not as bright as double its brightness.

If the First Light Is Exactly Twice as Bright as the Second