Effect Of Amplitude

Before we move on to the technicalities of the topic, let us relate it to practical life to give you a better understanding. For instance, one of your friends speaks to you in hushed tones, and she needs to lean in close for you to hear what she’s saying. Your friend calls out to you later that day from across the gymnasium. Even though she’s several metres away, her voice is now loud enough for you to hear her plainly. Obviously, the volume of sounds might fluctuate but can you, in any way, relate it with the effect of increasing the amplitude? If not, this article will give you the answer to this question and more. 

What is Amplitude?

The fact that sound is a kind of energy makes us hear the sound. For instance, a bell makes a sound when rung. Vibrations can be felt if one touches the bell. The bell is ringing; you can notice as you see it. Here, vibration is nothing but the to and fro motion of the ringing bell. The displacement from the mean location is measured by the amplitude of a wave (such as a sound wave). For a sound wave, the greatest displacement of a sound wave from the position of its equilibrium is defined as its amplitude. 

The greatest displacement of a particle from its equilibrium location is used for the amplitude of not just sound waves but any longitudinal wave. The effect of amplitude on a wave is massive, as we shall see further in this article. 

How is Amplitude Measured?

Basically, the wave size is described using the amplitude. The metre, designated by m, is the SI unit for measuring amplitude; however, it is occasionally measured in centimetres as well.

Effects of Changing Amplitude

In this section, we will analyse the effect of amplitude on a wave. Whether the sound is loud or not is determined by the amplitude of the sound wave. 

Louder noises correspond to higher amplitudes, whereas quieter sounds correspond to lower amplitudes. This is the effect of increasing the amplitude. Despite this, studies have shown that sounds at very low and very high frequencies are perceived as softer than sounds in the middle frequencies, even when their amplitudes are the same.

The amount of energy a wave carries or can carry is proportional to its amplitude. A significant quantity of energy is carried by a high amplitude wave, while a small amount of energy is carried by a low amplitude wave. A wave’s intensity is actually the average energy being transmitted across a unit area in unit time in a definite direction. An increase in the intensity of the sound is seen with the increase in the amplitude of the sound wave. This is the effect of amplitude on a wave. Higher-intensity sounds are regarded to be louder. Decibel (dB) is the commonest unit used to express relative intensities of sound.

Factors Affecting Amplitude

The loudness of sound is determined by the amplitude of sound waves. Let us now find the answer to the next question, ‘which factors affect the amplitude of a sound wave’?

• The amount of energy required for the source to generate sound.
• The properties of the media in which the wave is travelling.
• The source’s and the environment’s frequency responses.

Largely, these three factors affect the amplitude of a sound wave. 

Conclusion

With this article, we understood the effect of amplitude on a wave. We also understood that the loudness or volume of a sound wave is determined by its amplitude. A louder sound has a bigger amplitude, while a softer sound has a lower amplitude. The vibration of the source has a major role to play in determining the amplitude of a wave. This is because energy is transmitted to the medium only through its vibration. A bigger amplitude equates to more intense vibration, i.e., the molecules are moving faster back and forth. 

However, the sensitivity of the ear also influences the loudness of a sound. The volume we hear is thus determined by the amplitude of a sound wave as well as whether its frequency falls within a sensitive range for the ear.