The percentage of nitrogen in air by weight is around
A.75.5 percent
B.65.5 percent
C.24.3 percent
D.23.1 percent
E.20.3 percent
Category: Environmental Engineering Mcqs
Dark, black smoke from diesel engines usually results when engine is
A.Idling
B.Running at slow speeds
C.Running at light loads
D.Running at full speed but under load conditions
E.Running at full load and full speed
The total count of bacteria in portable water should not exceed
A.10,000 per c.c.
B.5000 per c.c.
C.998 per c.c.
D.10 per c.c.
Which of the following is the major source of pollutant hydrogen sulphide?
A.Decaying organic matter
B.Auto exhaust
C.Oil burners
D.Solar energy
E.None of the above
The average percentage of carbon and hydrogen in petrol may be roughly given as
A.50% C, 50% H2
B.85% C, 15% H2
C.15% C, 85% H2
D.70% C, 30% H2
Which of the following acts as ignition accelerator for C.I. engine fuels?
A.Acetone peroxide
B.Hydrogen peroxide
C.Aromatic compounds
D.n-heptane
Permissible noise level in small conference room is
A.10 to 15 dB
B.15 to 25 dB
C.35 to 40 dB
D.55 to 60 dB
The process of killing the ineffective bacteria from the water and making it safe for use is known as
A.Disinfection
B.Sterilization
C.Filtration
D.Purification
E.None of the above
For controlling the growth of algae, the chemical generally used is
A.Alum
B.Lime
C.Bleaching powder
D.Copper sulphate
E.Ozone
Alum increases
A.Hardness of water
B.Carbonates of water
C.Sulphates in water
D.Acidity of water
E.None of the above
