Question

which of the following activities can produce infrasonic waves?
a vacuum cleaner
thunder
a person talking
bird singing

Explanation:

Infrasonic waves have a frequency below \(20\) Hz. Thunder is known to produce infrasonic waves. A vacuum cleaner, a person talking, and a bird singing produce sounds in the audible range (\(20 - 20000\) Hz) or ultrasonic range (above \(20000\) Hz).

Answer:

Thunder.