Question

Sound becomes hazardous noise pollution at level above _______________ dB.
(a) 30
(b) 80
(c) 100
(d) 120

Answer 1

The decibel (symbol: dB) is a relative unit of measurement like one- tenth of a bel (B). It is used to express the ratio of 1 value of a power or field quantity to a difference, on a scale, the logarithmic quantity being called the power level or field level, respectively.

Complete step by step answer:
Sound levels are measured in decibels(dB) , the sound level of 80 or more dB can aptly be called noise which can cause serious hearing loss, tensions, high blood pressure, it can induce several disorders prematurely existing, such as hypertension, an increase in blood cholesterol level and is detrimental to health in other aspects when observed for more than maximum tolerable limit of 50 dB. Hence, the correct answer is 'Above 80 dB'.
- Auditory stimuli are sound waves, which are mechanical pressure waves that move through a medium, like air or water.
- There is no type of sound waves during a vacuum since there are no air molecules for the waves to move through.
- The speed of sound waves differs between altitude, temperature, and medium.
- There are many various causes of deafness. It is often hereditary or simply a part of the aging process.
- It is often triggered by a blast of bang, infections, the effects of poisons, or injury.
- The good news: there are solutions to successfully correct most kinds of deafness.
So, the correct answer is, ‘(b) 80 dB.’

Note: Sound is caused by simple but rapid mechanical vibrations of various elastic bodies. These when moved or struck so as to vibrate, communicate the same kind of vibrations to the auditory nerve of the ear, and are then appreciated by the mind.