Question

What is the approximate range of audible sound frequencies for a human with good hearing?
A. From 20 Hz to 2000 Hz
B. From 20 Hz to 20000 Hz
C. From 200 Hz to 20000 Hz
D. From 200 Hz to 200000 Hz

Answer 1

Hint: Study the concept of vibration. Learn about the frequency and amplitude of vibration and the types of vibration depending on their frequency range. Then find the frequency range which is audible for the human ear.

Complete Step-by-Step solution:
Vibration can be defined as a phenomenon where an object oscillates about an equilibrium position. The vibration can be a regular vibration such as the motion of a pendulum or it can be an irregular one.
Amplitude of a vibration can be given as the maximum distance the object covers in either side of the equilibrium position.
Frequency of a vibration is given by the number of vibrations occurring per second. It can be explained as a vibrating object is in to and fro motion. A complete vibration occurs when an object moves from one extreme position to the other and again moves back to the first extreme position. The number of complete cycles that occurs in a second is called frequency of the vibration. Unit of frequency is Hz(hertz). One hertz is equal to one complete cycle per second.
Now, 20 Hz frequency is one where the object completes 20 complete cycles per second. It is a very low frequency sound. This is called infrasound.
Vibration of frequency above 20,000 Hz is called ultrasound.
The audible range for human ears is from 20 Hz to 20000 Hz.
The correct option is (B)

Additional information:
The speed of a vibrating object is different in different positions. If the object is at the equilibrium position it will have the maximum velocity and if the object is in any of the two extreme positions it will have zero velocity.

Note: We cannot hear the infrasound. We cannot hear ultrasound also. Human ears are capable of hearing frequencies between 20 Hz and 20,000 Hz. This frequency range is called audible range.