write a composition in about 350 words on Noise pollution
Answers
The word noise has come from the Latin word nausia and is usually defined as unwanted on unpleasant sound that causes discomfort. Noise pollution is defined as “the unwanted sound dumped into the atmosphere that leads to health hazards”.
Over the years the general incidence of noise has been increasing due to the development of engines, technological machineries in industry, jet planes etc. which have contributed to an increasing noisy environment.
The human ear receives sound waves and these sets up oscillations in the ear drum. These oscillations cause movements of the three ossicles or small bones (malleus, incus and stapes) in the middle ear, behind the ear drum. The oscillation is then passed into the inner ear to the auditory nerve and on to the brain for identification and interpretation of the sound.
The ear is able to analyse sounds into frequency components. The range of an 18 year old person with perfect hearing is between 20 Hz (infra-audible) to 20,000 Hz (ultrasonic). Normally hearing is more acute in the frequency range of 2,000 to 5,500 Hz, but it falls off rapidly below 200 Hz and above 10,000 Hz.
However, the ear’s sensitivity range varies considerably from person to person and also with the age of the concerned person. Old aged people experience a progressive hearing loss of high frequency sounds which is called ‘presbycusis’.
The ear is susceptible to damage if it receives high intensity noise. However, there are some protective devices through reflex action which the ear can perform only for short duration. If the ear is exposed to noise of 90 dB or more for longer period (>10 milliseconds), then the tympanic membrane contracts, thus reducing sound transmission.
If