The weakest sound that can be heard by a person in a quiet environment is equivalent to ____________ decibel ?

Related Mcqs:

Which of the following fine dust removal equipments is the most efficient ?

A. Bag filter B. Scrubber C. Electrostatic precipitator D. Cyclone separator...

Deaeration of high pressure boiler feed water is done to reduce ___________________?

A. Foaming from boilers B. Its dissolved oxygen content C. Its silica content D. Caustic embrittlement...

Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxiate is ≥ _____________ percent?

A. 84 B. 88 C. 80 D. 92...

Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the_______________?

A. Forestation B. Rain C. Green house effect D. Vegetation...

Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called_________________?

A. Fumes B. Mists C. Smoke D. Aerosols...