Environmental Engineering in CE MCQs

Question 1

High noise levels produced during operation of fans and compressors can be reduced by using

Accepted Answer

Mufflers (silencers)

Answer

Accoustical absorbent

Answer

Lagging of noisy duct

Answer

None of these

Question 2

Pick out the wrong statement.

Accepted Answer

The characteristic of a green house body is that it allows the long wavelength incoming solar radiation to come in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere

Answer

Biological oxygen demand (B.O.D.) value of a sewerage sample is always lower than its chemical oxygen demand (C.O.D.) value

Answer

Environmental pollution by NOx emission is much higher by four stroke petrol engines as compared to the two stroke engines

Answer

Temperature in stratosphere rises with increasing altitude

Question 3

Bag filter design is predominantly dependent on gas temperature, as it affects the gas density & viscosity and the selection of filtering material. The pressure drop in a bag filter is

Accepted Answer

Both B and C

Answer

Inversely proportional to viscosity of gas

Answer

Proportional to the viscosity & density of the gas

Answer

Proportional to the pressure of the gas

Question 4

Fresh sewage is __________ in nature.

Accepted Answer

Alkaline

Answer

Acidic

Answer

Neutral

Answer

Highly acidic

Question 5

Threshold limit value (TLV) of CO in air is __________ ppm.

Accepted Answer

50

Answer

5

Answer

2000

Answer

5000

Question 6

Photochemical smog is formed from automobile exhaust

Accepted Answer

All of the above

Answer

By reaction of hydrocarbon & nitric oxide in presence of sunlight

Answer

Appears only on sunny days

Answer

Is harmful for crops and trees also besides causing eye irritation & asthma

Question 7

Exposure to SO2 containing chimney gases results in the

Accepted Answer

All of the above

Answer

Reduction in strength of leather & cloth

Answer

Acceleration of corrosion rates of metals

Answer

Increased drying & hardening time of paints

Question 8

The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria.

Accepted Answer

Aerobic

Answer

Anaerobic

Answer

Saphrophytic

Answer

Parasitic

Question 9

The main type of sludge gas evolved during sewage treatment in Imhoff tank is

Accepted Answer

CH4

Answer

CO2

Answer

CO

Answer

H2