Question

It is possible to recognise a person by hearing his voice even if he is hidden behind a solid wall. This is due to the fact that his voice
A. has a definite capacity
B. has a definite quality
C. has definite pitch
D. can penetrate the wall

Answer 1

Hint: Quality of sound helps us to distinguish between sounds of different people. Even if the amplitude and pitch are the same, we can tell the difference between two sounds by its quality. The waveform tells us the quality of sound.

Complete step by step answer:
Sound: A sound is the form of energy, which is produced by vibrating objects. This is the vibration which pushes the particles near it to form Compression (C) and Rarefaction (R).
Compression is a region of high density or high pressure. This high pressure is because particles get accumulated near the vibrating source.
Rarefaction is the region of low density or low pressure. The low pressure is because particles get dispersed near the vibrating source, when vibration moves backwards.

There are some characteristics of sound by which we are able to differentiate the sound, these are:
Pitch: Vibration produced by the object of different size and shape, produces different frequency of sound. This is known as Pitch.
High pitch sound has a high frequency and low pitch sound has low frequency.

Loudness: To understand loudness, we have to understand the meaning of amplitude. The maximum disturbance in the medium i.e. created by sound source is called amplitude. And is represented by letter A.
The amplitude of a sound wave is determined by the force of vibration of the object. Higher the force , higher the amplitude.
For example, if we hit the fork lightly, we hear a soft sound because we produced a sound wave of less energy or less amplitude.
And if we hit the fork hard, we hear a loud sound because the sound wave has high energy or high amplitude associated with it.
As the sound wave moves further away from the source, the amplitude as well as its loudness decreases. Therefore, louder sounds can travel a large distance.

Quality of sound: The quality of sound is that characteristic which helps us to differentiate one sound form from another. Even if they have the same pitch and loudness.
Pleasant sounds are good to listen to because they have rich quality.
Answer is option B. has definite quality.

Note: Quality of sound is also known as Timbre. We recognize different sounds by its quality. Quality of sound of different instruments is determined by its waveform. Even if two sounds have the same frequency or pitch and same amplitude or loudness, its quality can be found by just looking at the waveform.
Tuning fork has curve wave form while violin has pointed wave form.