1. Source of sound:

Sound is produced by the vibration of objects. Sources of sound can be natural and man-made.

2. Natural frequency:

The frequency by which a body vibrates when it is set to vibration.

3. Characteristics of sound:

(i) The sharpness of sound is known as pitch. It depends on the frequency of sound.

(ii) Loudness: It is the measure of audibility of a person. It depends on the amplitude of vibration and the sensory ability of the ear. The unit of loudness is decibel $(dB)$ . This is measured using a device named decibel meter.

4. Propagation of sound:

Sound needs a medium to propagate.

5. Hearing:

The sense organ ear helps us to hear sound. Damage to ear can cause loss of hearing.

6. Limits of Audibility:

(i) A normal human being can hear sounds between $20 Hz$ and $20 kHz$ .

(ii) Sound with frequency less than $20 Hz$ is known as infrasonic and more than $20 kHz$ is known as ultrasonic.

7. Uses of ultrasonic waves:

Ultrasonic waves are used in SONAR and in medical fields.

8. Noise pollution:

(i) Noise is produced due to irregular vibration and is unpleasant to hear.

(ii) Noise pollution is produced due to unpleasant sounds and excess exposure to it can affect body and health.

Mridangam is the musical instruments in which sound is produced by beating the diaphragm of musical instrument.

Important Questions on Sound

Learn and Prepare for any exam you want !