What is the valley (lowest portion) of a sound wave called?

Correct option is D

The correct answer is (d) Trough.
· The valley or the lowest point of a sound wave is called the trough. In a sound wave, the trough is the point where the pressure is at its minimum, and it is opposite to the crest, which is the highest point where the pressure is maximum. Sound waves are longitudinal waves, but when represented graphically as transverse waves, the troughs and crests help visualize the changes in pressure and displacement.
Information Booster:
· Crest: The peak or highest point of a sound wave, where the pressure is maximum.
· Amplitude: The height of the wave, measured from the equilibrium position to the crest or trough, indicating the wave's intensity.
· Wavelength: The distance between two consecutive crests or troughs.