[Physics Class Notes] on Loudness of Sound Pdf for Exam

The sounds we encounter in our daily lives vary, and we are equipped with mechanisms to analyze and comprehend these variations. Mothers have a different voice from those of the children they speak to. Have you ever thought about why everyone has a different voice? We need to understand the loudness of sound, its pitch, and the difference between them.

What is the loudness of sound? Which factors determine it?

Answer:

There is a relationship between the loudness of a sound and its amplitude. In general, loudness refers to how large the amplitude of the sound wave is. The decibel (dB) scale for measuring loudness is directly proportional to the square of the amplitude of the vibration. Thus, noise is defined as sounds above 80 dB. 

Explanation:

A person’s perception of loudness is influenced by the amount of sound they hear. A sound’s volume is determined by its intensity, which is itself governed by its frequency. Sounds are measured by their intensity or the energy they hold. Intensity is measured in decibels (dB). In this way, the loudness of sounds is determined by its intensity. There are two factors that determine how intense a sound is: the size of the sound waves and the distance from their source.

• Sound waves are measured according to their amplitude.

• Wave amplitude is determined by the energy that caused them.

• Waves with larger amplitudes have more energy and are more intense, so they are louder.

 

In sound waves, the amplitude is directly associated with loudness, since all waves have the same amplitude. An ocean wave on a calm day may only be a foot high, whereas a surf wave can reach heights of 10 feet or more. As the amplitude increases during a storm, it may reach 40 to 50 feet.

Pitch of sound

• Depending on how fast the waves vibrate, the effect is different.

• Sound that has a high pitch and a high frequency is called shrill or shrill sound. A sound’s pitch is expressed as its frequency of vibration if it has a lower pitch.

• While birds produce high-pitched sounds, lions produce low-pitched sounds when roaring.

• An average woman’s voice has a higher pitch than an average man’s.
  

Pitch vs Loudness

Although these two phenomena sometimes appear to be the same, they are not exactly the same. The key difference is the quality of the tone. Sound pitch is a response our ears have to a sound’s frequency. In contrast, loudness is determined by the strength of the wave. Generally speaking, pitch accounts for the difference in voice quality between individuals.

 

The Pitch and loudness of sounds are determined by their frequency and amplitude, respectively. It is amazing that trained musicians have the ability to detect a difference in frequency between sounds that is as little as 2 Hz.

 

The Loudness of Sound Formula

L = log (I)

 

Where I: Intensity of sound.

 

Difference of loudness, L₂ – L₁ = 10 log₁₀ [(frac {I_1}{I_0})]

The Intensity of the Sound

Accordingly, the intensity is defined as the ratio of energy per unit time per unit area, and since the ratio of energy to time is the same as the power per unit area, the intensity is simply the power per unit area.

 

Intensity = [frac{text{Energy}}{text{(Time * Area)}}] or Intensity = [frac{text{Power}}{text{Area}}]

 

The units used to express the intensity of a wave of sound are Watts per meter².