Which one of the following pollutants or pairs of pollutants is formed due to photochemical reactions?
Photochemical reactions form O3, PAN, formaldehyde, etc.
Which of the following pairs are correctly matched?
Select the correct answer using the codes given below:
Reverberation time is the time required to reduce the intensity to one-millionth of its initial value.
Sound level (dB)
TTS (Temporary Threshold Shift) is temporary impairment of hearing acuity as indicated by change in the threshold of audibility PTS (Permanent Threshold Shift) is related to permanent hearing loss. The sound foci are formed when sound waves are reflected from concave surface.
The following is a well known formula for estimating the plume rise:
where the letters have their usual meaning.
The estimated plume rise (by the above formula) with a stack gas having heat emission rate 2000 kJ/s, the wind speed 4 m/s, stack gas speed 8 m/s inside a stack diameter of 1 m at the top is
Wind Speed u = 4 m/s
Stack gas speed Vs = 8 m/s
Diameter d = 1 m
Heat rise Qh = 2000 kJ/s
We know that effective height of stack,
Which one of the following procedures is used for sampling of the flue gas in a chimney for SPM?
Which one of the following units is employed for the removal of particulate matter above 50 μ in size?
Acoustics of an auditorium is considered to be excellent when its reverberation time is between
For excellent acoustic conditions, reverberation time should be between 0.5 to 1.5 seconds.
Which type of light energy is effectively absorbed by CO2 in the lower boundary of the troposphere?
CO2 is major green house gas and absorbs long wave radiations like infrared radiation.
Which one of the following is the correct sound intensity expression with usual notations?
What type of noise can be abated by providing lining on walls and ceiling with sound absorbing materials?
Sound absorbing materials reflect the noise and they are mostly used in theatres etc.
Which is the major pollutant present in photochemical smog?
Photochemically, the NOx and hydrocarbons are two groups of chemical compounds which are the necessary ingredients for the production of photochemical smog.
The end product of photochemical reactions is photo chemical smog consisting of air contaminants such as O3, PAN, aldehydes, ketones, alkyl nitrates and carbon monoxide.