Air Pollution and Control Week 10 Nptel Quiz Answers
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Air Pollution and Control Week 10 Nptel Quiz Answers (Jan-Apr 2025)
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1. A cyclone has an inlet width of 20 cm and five effective turns (N = 5). The gas temperature is 350⁰K, and the inlet velocity is 10 m/s. The average particle density is 1.5 g/cm³. What is the cut diameter (particle size collected with 50% efficiency)? The viscosity of air at 350⁰K is 0.0748 kg/m-h.
a. 6.94 µm
b. 8.33 µm
c. 12.14 µm
d. 15.55 µm
2. In a bag house filter, the incoming velocity of the gas is 800 m³/min. The filtering velocity is 4 m/min. Each bag is 20 cm wide and 3 m in length. If the spacing between each bag is 30 m and the wall is 30 cm, the number of bags required is________.
a. 95
b. 106
c. 144
d. 225
3. An electrostatic precipitator, in which the collection plate area is 100 m², gas flow rate is 3 m³/s, and collection efficiency is 99.5%. The migration velocity is______(in m/s):
a. 0.16
b. 0.67
c. 1.54
d. 2.15
4. Single-stage electrostatic precipitator consisting of two sections formed by plates 5.0 m wide and 7.0 m high on 25 cm centers, handling a gas flow of 3 m³/s. Assume that the migration velocity is 12 cm/s. The collection efficiency of a horizontal flow is__________(in %).
a. 98.55 %
b. 98.25 %
c. 99.63 %
d. 99.25 %
5. Gravitational settling chamber under the following conditions:
- Air: Horizontal velocity is 1 m/s
- Temperature is 75⁰C
- Particle: Specific gravity is 1.5
- Chamber: Length is 10 m and Height is 2 m
- At 75⁰C, viscosity of air is 2.1×10⁻⁵ kg/m-s
The minimum size of the particle is____________, that will be removed with 100 per cent efficiency.
a. 65.28 µm
b. 71.68 µm
c. 83.55 µm
d. 90.67 µm
Air Pollution and Control Week 10 Nptel Quiz Answers (Jan-Apr 2025)
6. Which of the following pollutants is not included in the revised National Ambient Air Quality Standard (NAAQS, 2009)?
a. Ozone
b. Benzene
c. Arsenic
d. Cadmium
7. What is the annual permissible limit for PM2.5 in ambient air as per WHO guidelines 2021?
a. 5 µg/m³
b. 10 µg/m³
c. 25 µg/m³
d. 50 µg/m³
8. What is the primary goal of the National Clean Air Programme (NCAP) in India?
a. To completely eliminate PM emissions by 2025
b. To achieve a 20–30% reduction in PM2.5 and PM10 levels by 2024
c. To reduce vehicular emissions in all cities
d. To promote urbanization in non-attainment areas
9. What is the focus of the Graded Response Action Plan (GRAP)?
a. Managing waste in urban areas
b. Reducing air pollution during severe episodes in Delhi NCR
c. Expanding public transportation networks
d. Implementing electric vehicle subsidies
10. Which Indian policy promotes the adoption of electric vehicles to reduce vehicular emissions?
a. National Electric Mobility Mission Plan (NEMMP)
b. Make in India Program
c. National Renewable Energy Policy
d. National Highway Development Project
Air Pollution and Control Week 10 Nptel Quiz Answers (Jan-Apr 2025)
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