Sound (Physics)

The intensity of sound in normal conversation is 30-60 decibel. The sound of 50 decibel is enough to wake up a sleeping person.

To remain continuously in the sound of 80 decibel proves to be harmful. 90 decibel is the maximum limit to tolerate any noise by human being.

Sound above 80 decibel is considered hazardous noise pollution. Continued exposure to high levels of noise results in fatigue, hearing loss or even total loss of hearing, changes in blood circulation, changes in breathing patterns etc.

Sound above 80 decibel is considered hazardous noise pollution. Continued exposure to high levels of noise results in fatigue, hearing loss or even total loss of hearing, changes in blood circulation, changes in breathing patterns etc.

The average sound level in normal conversation is 60 decibel, It is appropriate for human ears. The sound higher than 80 decibel can cause damage to the ear cells.

A sound wave's amplitude is the change in pressure as the sound wave passes by. If you decrease the amplitude, you are making the sound softer. The amplitude of a wave is related to the amount of energy it carries.

A high amplitude wave carries a large amount of energy, a low amplitude wave carries a small amount of energy. The average amount of energy passing through a unit area per unit of time in a specified direction is called the intensity of the wave.

As the amplitude of the sound wave increases, the intensity of sound increases. Sounds with higher intensity are perceived to be louder. Relative sound intensities are often given in units named decibel (dB).

The speed of sound is greater in steel than in air, as sound reaches first by rail track and then by air. Therefore the boy hears the sound twice.

The Speed of sound depends upon the nature of medium through which it propagates. Speed of sound is maximum in solids while minimum in gases. Speed of sound is less in glass medium than in aluminium medium.

Increase in temperature results to increase in the speed of sound in any medium. Hence, among the given statement, only statement I is true

When a sound wave goes from one medium to another, its frequency usually remains the same (because it is like a driven oscillation and maintains the frequency of the original source) while its speed and wavelength are changed.

The amplitude of sound is also changed as it decreases with distance from its source.

String length, diameter, density and tension determine the frequency in which it will vibrate. Since other three are fixed, it is the tension that sitarist tries to adjust to tune its natural frequency.

And while playing the Sitar, he changes the effective length of the string by touching the string at different points with his finger. This is how we get different melodious notes (of varying frequency).

Amplitude/intensity of sound is not determined by the tension in the string since it depends on how the Sitarist is playing. Even with a perfectly taut string, he can produce low or very high sound.

But he cannot vary its natural frequency and that's why he has to adjust the tension beforehand. So, the correct answer is (a).

Musical sound can differ from each other with respect to the following three characteristics:

1. Loudness (intensity)

2. Pitch (shrillness)

3. quality (timber)

But quality (timber) is that characteristic of a musical sound which enables us to distinguish between two sounds even if they have the same pitch and loudness.