Engineering Questions with Answers - Multiple Choice Questions

# Environmental Engineering MCQ – Dispersion of Air Pollutants, Contol of Gaseous Pollutants

1 - Question

When environmental Lapse Rate (ELR) is less is than Adiabatic Lapse Rate (ALR), then which of the following occurs?
a) Sub adiabatic lapse rate
b) Super adiabatic lapse rate
c) Neutral lapse rate
d) Adiabatic lapse rate

Explanation: When the temperature increases with an increase in altitude, Sub adiabatic lapse rate occur and there will be stable environment.

2 - Question

_______ occurs when atmospheric temperature increases with height.
a) Negative lapse rate
b) Super adiabatic lapse rate
c) Neutral lapse rate
d) Positive lapse rate

Explanation: Under negative lapse rate, the colder air is below the warmer air. It can be occurred near the earth’s surface.

3 - Question

When environmental Lapse Rate (ELR) is equal to the Adiabatic Lapse Rate (ALR), then which of the following occurs?
a) Sub adiabatic lapse rate
b) Super adiabatic lapse rate
c) Neutral lapse rate
d) Adiabatic lapse rate

Explanation: When the temperature is constant with height, then neutral lapse rate occurs.

4 - Question

The wet adiabatic rate is greater than the dry adiabatic rate.
a) True
b) False

Explanation: The value of wet adiabatic rate is 60C per 1000m whereas of dry adiabatic rate is 9.80C per 1000m.

5 - Question

When Environmental Lapse Rate (ELR) is greater than Adiabatic Lapse Rate (ALR), then which of the following occurs?
a) Sub adiabatic lapse rate
b) Super adiabatic lapse rate
c) Neutral lapse rate
d) Adiabatic lapse rate

Explanation: In Super adiabatic lapse rate, the environment is unstable due to the quick dispersion of pollutants.

6 - Question

Which of the following is the absorption unit?
a) Cyclone collector
b) Plate tower
c) Gravitation settling chamber
d) Dynamic precipitator

Explanation: Cyclone collector, Gravitation settling chamber and Dynamic precipitator are used to remove particulate matter, whereas Plate tower is used to remove gaseous matter and is an absorption unit.

7 - Question

Which of the following catalyst is used for removing hydrocarbon from gaseous pollutant in combustion unit?
a) Platinum
b) Activated alumina
d) Potassium permanganate

Explanation: Activated alumina is used as a catalyst for removing gaseous pollutant called hydrocarbons from the air. The concentration of hydrocarbon emitted from automobiles is 300-1000 mg/l.

8 - Question

Which of the following is not a part of adsorption unit?
a) Packed towers
b) Multiple fixed bed
c) Fluidized bed
d) Moving bed

Explanation: Packed tower is a part of the absorption unit, whereas multiple fixed bed, fluidized bed and moving bed are the examples of absorbers.

9 - Question

Which of the following is a bulk phenomena?
c) Absorption
d) Sorption

Explanation: Adsorption is a bulk phenomena, whereas absorption is a surface phenomena.

10 - Question

Which of the following is not an adsorbent?
a) Molecular sieves
b) Activated carbon
c) Activated alumina
d) Water