Question

State any four factors on which the loudness of sound depends.

Answer 1

Loundness of sound:

1. It refers to how loud or soft a sound seems to a distant listener.
2. The loudness of sound is determined by the intensity or amount of energy present in sound waves and is expressed in decibels.
3. As the level of decibel gets higher sound waves have greater intensity and sounds are louder.

Factors on which loudness of sound depends:

1. Amplitude of sound wave- The amplitude of a sound wave is the measure of the height of the wave. The amplitude of a sound wave can be defined as the loudness or the amount of maximum displacement of vibrating particles of the medium from their mean position when the sound is produced.

Loudness ∝ amplitude²

2. Distance from sound source- Less the distance from the source of sound more the loudness of sound, therefore loudness of sound is inversely proportional to the distance from the source.

Loudness ∝ $\frac{1}{dis\tan ce}$

3. Density of medium- More the density of medium more the loudness. For example- the loudness of the sound of the train will be more on a railway track as compared to in air as the density of iron is more than air.

4. Surface area of vibrating bodies- More the surface area of vibrating bodies, the more will be the loudness of sound. For example - the loudness of the sound of beating a stick on a drum with less surface area will be less than beating it on a drum with more surface area.

Thus sound depends on the amplitude of the sound wave, distance from the sound source, the density of the medium and the surface area of vibrating bodies.