Question

Plantation of rows of trees and shrubs along roads, rails, around residential complexes, educational institutes, etc. is called
A. Green muffler
B. Shelter belt
C. Wind break
D. Both B and C

Answer 1

Hint:- An unwanted sound in the environment is called noise. An excessive and unpleasant noise is categorised as a noise pollution. It tends to have harmful implications on the general health of human or animal life. Commercial and industrial activities, construction sites contribute to noise pollution in the nearby locality.

Complete step-by-step solution:- In British English, muffler refers to a ‘silencer’. It is an acoustic tool particularly engineered to reduce loud noise released by an internal combustion engine exhaust. Similarly, a green muffler is a scheme or technique in which 4-6 rows of green plants are planted around the cities. This is done mostly in populated areas or noisy places like along roadsides, hospitals, etc. Since, trees are good noise buffers; they muffle the urban noise very effectively. This strategic planting helps to keep a check on noise emitted by vehicles and factories and also from airports.
So, the correct answer is option (A), Green Muffler.
Additional information:
In adults, sounds greater than 140 dB and in children more than 120 dB can cause severe irreversible damage of the auditory nerve.

Note:-
The level of sound in the environment is measured in decibels (dB) using a device called a sound level meter. Any level of sound up to 64 dB can be well tolerated. A whisper sound is measured to be 30 dB and is considered quiet. The World Health Organization has recommended an industrial noise limit to be 75 dB. Any sound above 80 dB causes discomfort in man and is considered hazardous. It has been reported that damage occurs at lower sound levels, which accumulates over time and affects the hearing system. Loud sound causes wear and tear in the ears and reduces the hearing capacity.