Question

Differentiate between:
1.
Crest and trough.
2. Infrasound and ultrasound.​

Answer 1

A crest is the highest point of a wave.

A trough is the lowest point of a wave.

Infrasound is sound below the limit that humans can hear, below 20 Hz.

Ultrasound is sound above the limit that humans can hear, above 20,000 Hz.