Here are one line statements that might be useful for your preparation for the GATE and PSUs examinations from the subject "Noise Pollution".
- To express sound levels in decibels, sound pressure levels are usually adopted on a reference scale of 20 uPa(micro-Pascals).
- 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.
- 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
- Acoustics of an auditorium is considered to be excellent when its reverberation time is between 0.50 to 1.50 sec.
- Reflection noises can be abated by providing lining on walls and ceiling with sound absorbing materials.