Question

The loudness or softness of a sound is determined basically by
a) frequency
b) pitch
c) amplitude
d) phase

Answer 1

Hint: To understand what the loudness of sound depends on we need to know what the terms in the options mean. The loudness of the sound is basically the intensity of the sound. The intensity of the sound is given as energy per unit area of the sound wave. Hence will consider an analogy i.e. striking a guitar harder and softer and accordingly conclude on what does the loudness of the sound depends on.

Complete step-by-step answer:
To begin with let us define some of the terminologies.
The frequency of the sound wave is the number of oscillations of the sound wave in unit time.
The pitch of the sound is how high or low the loudness of the sound is i.e. for the same loudness there is some difference in the sound heard by the listener.
Amplitude of the sound wave determines how higher the sound wave vibrates from its mean position.
Phase is the lag between two sound waves i.e. they both start at different points of time.
Let us strike initially a guitar string very slowly. The loudness of the sound will not be that much. Now let us say we hit the guitar string more harder than the previous. The loudness of the sound heard by one will be greater than before. When we hit harder we supply more energy to the guitar string. It is found that the energy of the sound wave is directly proportional to the square of the amplitude of the wave. From this definition we can conclude that the greater the energy of the wave greater is the amplitude. Hence from the above analogy we can conclude that the loudness or the softness of the sound depends on its amplitude.

So, the correct answer is “Option c”.

Note: The loudness of the sound is directly proportional to the square of the amplitude. Hence if we increase the amplitude of the sound by some factor k, then the loudness of the sound will increase by the square of that factor k. It is also to be noted that the pitch of the sound is determined by the frequency of the sound.