Environmental Engineering (Part-2) (General Engineering) (SSC JE)

Total Questions: 50

1. The A-weighted scale covers sounds of frequencies from– [RRB JE 29.08.2015 (Shift-III) ]

Correct Answer: (a) 800 to 3000 Hz
Solution:

The ambient noise levels are measured in the A-weighted SPL, abbreviated as dBA. This scale resembles the audible response of human ear. Sounds of frequencies from 800 to 3000 Hz are covered by the Aweighted scale.

2. A water borne disease poliomyletitis is caused by : [RRB S.S.E. 02.09.2015 (Shift-III) ]

Correct Answer: (a) viruses
Solution:

Water borne diseases– Bacteria– Typhoid fever, cholera, Bacillary, Dysentry etc.
Protozoa– Amoebic dysentery
Virus– Jaundice, Poliomyelitis
Note– Measles is not a water borne disease
• Measles is caused by morbillivirus, which is mostly seen in the winter and spring.

3. In potable water, the permissible limit of nitrate nitrogen is : [RRB S.S.E. 02.09.2015 (Shift-III) ]

Correct Answer: (a) 10 mg/lit
Solution:

In potable water, the permissible limit of nitrate nitrogen is 45 mg/lit.

4. Carbonmonoxide forms carboxyhemoglobin in human blood that may cause : [RRB S.S.E. 02.09.2015 (Shift-III) ]

Correct Answer: (b) decreased oxygen carrying capacity
Solution:

Carbon monoxide is a poisonous gas released into the atmosphere by the incomplete combustion of fossils fuels.

• It has a more affinity for hemoglobin than O₂ when combines with hemoglobin in red blood cells to form carboxy hemoglobin. Carboxy hemoglobin decreases the oxygen carrying capacity of blood.

5. The average concentration of ozone present in the stratosphere is approximately : [RRB S.S.E. 02.09.2015 (Shift-III) ]

Correct Answer: (c) 10 ppm
Solution:

The average concentration of ozone present in the stratosphere is approximately 10 ppm and the average concentration of ozone in the troposphere is 0.05 ppm. The troposphere is the lowest layer of the earth's atmosphere.

6. The prescribed water consumption for restaurants is [RRB JE 29.08.2015 (Shift-I) / RRB JE 30.08.2015 (Shift-III) ]

Correct Answer: (c) 70 litres per seat per day
Solution:

The prescribed water consumption for restaurants is 70 litres per seat per day.
• As per IS : 1172-1963, under normal conditions, the domestic consumption of water in India is about 135 liters/day/capita.

7. The continuous exposure of pollutant benzo (α) pyrene may cause– [RRB JE 29.08.2015 (Shift-I) ]

Correct Answer: (d) lung cancer
Solution:

The continuous exposure of pollutant benzo (α) pyrene may cause lung cancer. Benzo pyrene can be found in surface water, tap water, rainwater, ground water, wastewater and sewage sludge.

• If benzo (α) pyrene is on your skin when you are being exposed to sunlight or ultraviolet light, the risk of skin cancer is greater.

8. The noise level of 10 dB is how many times more powerful than the noise level of 1 dB– [RRB JE 29.08.2015 (Shift-I) ]

Correct Answer: (b) 10 times
Solution:

The intensity of sound is increased by 10 times. Let I' be the intensity of previous sound. Intensity of recent sound I' = 10 I

9. The spacing between two bars in fine screen is– [RRB JE 29.08.2015 (Shift-II) ]

Correct Answer: (c) 10 mm
Solution:

Fine size screens– It have perforation of 1.5 mm to 3 mm in size. These screens, however, yet clogged very often, and need frequent cleaning. The fine screen is usually made of woven wire mesh with an opening not more than 6 mm² .

Medium size screens– The spacing between the bar is about 6 to 40 mm, it is screenings usually contain same quantity of organic material, which may putrefy and becomes offensive and must, therefore, be disposal by incineration of burial (not by dumping).

Coarse screens– It is also known as racks and the spacing between the bar is about 50 mm or more. These screens do help in removing large floating materials.

10. In villages, to disinfect the well water, the most common disinfectant used is– [RRB JE 29.08.2015 (Shift-II) ]

Correct Answer: (b) potassium permanganate
Solution:

This is the most common disinfectant used in the village for disinfection of dug well water, pond water or private square of water.

In addition to the killing as bacteria it also reduces the organic matters by oxidising them. The usual dose of KMnO₄ is 1-2 mg/litre of water with contact period of 4-6 hours. It efficiency is only 98%.