Answer:
Wave X is the brightest light
Step-by-step explanation:
The amplitude of a wave refers to the maximum upward or downward displacement of a wave from its rest position. This implies that the amplitude is the measured distance from rest position to crest position. Similarly, the amplitude is also measured from the rest position to the trough position.
The crest of a wave is the point on a travelling wave that has the maximum amount of positive or upward displacement from the rest position. The trough of a wave is the point on the travelling wave that has the maximum amount of negative or downward displacement from the rest position.
From the wave diagrams shown in the attachment below, the wave that shows the highest amount of upward or downward displacement from the rest position (x - axis) is wave X. Since the brightness of a light wave increases with increaese in amplitude, wave X will have the highest amount of brightness.