Question

The waves produced by simple pendulum (having time period $2$ seconds) are.

• A. Infrasonics
• B. Audible
• C. Ultrasonic
• D. None of these

Answer 1

Answer: (A)

Infrasonics

According to the above discussion,

Sound	Frequency
Infrasonics	f < 20 kHz
Ultrasonic	f > 20 kHz

Time period of simple pendulum $T=2s$

Frequency of pendulum $f=\frac{1}{T}=\frac{1}{2}=0.5Hz$

Because frequency sound produced by a simple pendulum is less than 20 Hz, we can say that sound waves will be Infrasonics.

Option A