Noise Pollution (civil Engineering)-GATE, PSUs one liners

Hello there,

Here are one line statements that might be useful for your preparation for the GATE and PSUs examinations from the subject "Noise Pollution".

1. To express sound levels in decibels, sound pressure levels are usually adopted on a reference scale of 20 uPa(micro-Pascals).
2. Two sources generate noise levels of 90 dB and 94 dB respectively. The cumulative effects of these two noise levels on the human ear is 95.5 dB.
3. Pairs :  a) Ringlemann : To grade density chart of smoke   b) Pneumoconiosis : Disease caused due to coal dust  c) PAN : Secondary air pollutant   d) NIPTS : Responsible for permanent hearing loss   e) Sound foci :Formed when sound waves are reflected from convex surface   f) TTS : Responsible for temporary hearing loss
4. Acoustics of an auditorium is considered to be excellent when its reverberation time is between 0.50 to 1.50 sec.
5. Reflection noises can be abated by providing lining on walls and ceiling with sound absorbing materials.

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