The loudness of sound is determined by the (a) amplitude of vibration (b) the ratio of amplitude and frequency of vibration (c) frequency of vibration (d) product of amplitude and frequency of vibration

Answer: (a) Amplitude of Vibration

Explanation 

The degree of sensation of sound produced in the ear refers to the loudness of sound. It is measured in decibels and is determined by the amplitude of vibration. There is a direct relationship between the two, that is, the amplitude of a faint or feeble sound is less whereas the amplitude of vibration is greater in case of a louder sound. This magnitude of amplitude is determined by what number are the molecules being dislocated by the vibration – Greater the displacement of molecules, the larger is the amplitude created while lesser the displacement of molecules, the smaller is the amplitude of vibration created.