Hearing may be damaged by excessive noise. So our ear sometimes need protection from continuous loud sound. Hearing damage depends on the sound intensity level (decibel level) and the exposure time, and the exact combinations vary for different people. Normally, at `90 dB`, it takes `8 hours` or less for the damage to receptor nerves to occur. further, it is found that if the sound level is increased by `5 dB`, the safe exposure limit is cut to half.
(a) How long will it take for a sound of a very loud lawn mower (or a motorcycle) of `95 dB` to damage the hearing ?
(b) What is the nonstop exposure time for a `105 dB` sound to damage the ear ?
( c) What should be done to protect the society from the danger of losing the divine gift of hearing power ?

Explanation

(a) Intensity level of a lawn mower, i.e., `95 dB above 90 dB`. Obviously, this sound takes `(1//2)(8 h)`, i.e., `4 h` to damage hearing.
(b) Intensity level of `105 dB is 15 dB` (i.e., 3 times 5 dB) above `90 B` and as such it takes `(1//2)^3 (8 h)`. i.e., `1 h` to damage the ear.
( c) Steroes and other sound system should be played at low intensity, rock concert `(110 dB)` should be attended only for a small duration and that too if very essential. We should protect our ears from gunshot blasts, firecrackers and loud sporting events. Late night celebrations (jagrans, kirtans, Marriage functions) should be without loudspeakers as they are meant for those who are present there and not for the general public.