UGC-NET (NTA) Environmental Sciences, June-2019

Total Questions: 100

91. According to National Ambient Air Quality Standards (NAAQS) annual average concentration (µg/m³) for SO₂ and NO₂ in ecologically sensitive areas are:

Correct Answer: D. 20 and 30 respectively

92. A 100 mL sample of paper industry effluent is digested in acidified dichromate solution and by back titration it is found that 5 x 10⁻⁴ mol of dichromate has been consumed in chemical oxidation. What is COD (mgO₂L⁻¹) of the sample?

Correct Answer: C. 240

93. Acid mine drainage from underground mines occurs as:

Correct Answer: B. Point discharge
Solution:

Generally, acid mine drainage from underground mines occurs as point discharges. A major source of acid mine drainage may result from the closure of a mine. When a mine is abandoned and dewatering by pumping ceases, the water level rebounds. However, the workings often act as drainage systems so that the water does not rise to its former level.

94. Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R):

Assertion (A): If BOD level of water in a reservoir is less than 5 mgL⁻¹, it is highly polluted.
Reason (R): High BOD means high microbial activity.
Choose the correct answer from the options given below.

Correct Answer: D. (A) is false, but (R) is true
Solution:

BOD indicates the amount of putrescible organic matter present in water. Therefore, a low BOD is an indicator of good quality water, while a high BOD indicates polluted water. Dissolved oxygen (DO) is consumed by bacteria when large amounts of organic matter from sewage or other discharges are present in the water.

If BOD level of water in a reservoir is less than 5 mg/L, it is low polluted.

95. Match List-I (Environmental Pollutant) with List-II (Instruments Used for Analysis):

List-I (Environmental Pollutant)List-II (Instruments Used for Analysis)
(a) PAHs(i) AAS
(b) Heavy metals(ii) UV-Vis spectrophotometer
(c) Sulphate ions(iii) Electrophoresis
(d) Nucleotides(iv) HPLC

Choose the correct answer from the options given below:

(a)(b)(c)(d)
A.(i)(ii)(iii)(iv)
B.(ii)(iii)(iv)(i)
C.(i)(ii)(iv)(iii)
D.(iv)(i)(ii)(iii)
Correct Answer: A.
Solution:

(i) High-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in human hair.

(ii) Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in part of the ultraviolet and the full, adjacent visible spectral regions. This means it uses light in the visible and adjacent ranges.

(iii) Electrophoresis is a technique commonly used in the lab to separate charged molecules, like DNA, according to size. Gel electrophoresis is a technique commonly used in laboratories to separate charged molecules like DNA.

96. Which one among the following do all the terrestrial biomes have in common?

Correct Answer: D. Biodiversity pattern that is directly proportional to latitude
Solution:

Terrestrial ecosystems are known for their diversity; they are grouped into large categories called biomes. Grouping these ecosystems into just a few biome categories obscures the great diversity of the individual ecosystems within them.

Terrestrial biomes on Earth are each distinguished by characteristic temperatures and amount of precipitation. Comparing the annual totals of precipitation and fluctuations in precipitation from one biome to another provides clues as to the importance of abiotic factors in the distribution of biomes.

Temperature variation on a daily and seasonal basis is also important for predicting the geographic distribution of the biome and the vegetation type in the biome. The distribution of these biomes shows that the same biome can occur in geographically distinct areas with similar climates.

97. The marks of students in a certain course averaged 75 over a period of years. A class of 50 students has a mean marks 70 with a standard deviation of 10. To test whether this lower mean can be attributed to ordinary sampling variation, t-statistic is required. The value of t is:

Correct Answer: A. -3.5

98. As per the amended rules for the implementation of Forest Rights Act of 2006, the transit passes for the transport of minor forest produce are issued by:

Correct Answer: A. Gram Sabha
Solution:

The Union ministry of tribal affairs has notified the amended rules for the implementation of the Forest Rights Act (FRA) of 2006. The new rules say that forest dwellers can transport minor forest produce (MFP) by "any appropriate means of transport" and mandate that transit passes for the same will be issued by a committee constituted by the Gram Sabha.

The draft rules issued in July were silent on transit passes. "This would have led to a threat of opening up of forest for unsustainable use. But allowing the forest department to issue transit passes, as has been done so far, would have defeated the purpose.

The ministry has done the right thing by empowering gram sabha to issue transit passes,' According to the new rule, the committee constituted under the gram sabha will prepare conservation and management plan for community forest resources after forest dwellers' rights on such resources are recognised.

99. As per Occupational Safety and Health Administration, hazard communication pictogram of flame over circle represents the hazardous waste, to be an:

Correct Answer: A. oxidizer
Solution:

As of June 1, 2015, the Hazard Communication Standard (HCS) will require pictograms on labels to alert users of the chemical hazards to which they may be exposed. Each pictogram consists of a symbol on a white background framed within a red border and represents a distinct hazard(s). The pictogram on the label is determined by the chemical hazard classification.

Flame Over Circle

100. First State to make rainwater harvesting compulsory in India is:

Correct Answer: B. Tamil Nadu
Solution:

The feasibility of rainwater harvesting in a particular locality is highly dependent upon the amount and intensity of rainfall. Other variables, such as catchment area and type of catchment surface, usually can be adjusted according to household needs.

As rainfall is usually unevenly distributed throughout the year, rainwater collection methods can serve as only supplementary sources of household water. The viability of rainwater harvesting systems is also a function of the quantity and quality of water available from other sources, household size, per capita water requirements. and budget available.

Tamil Nadu was the first state to make rainwater harvesting compulsory for every building to avoid groundwater depletion. The scheme was launched in 2001 and has been implemented in all rural areas of Tamil Nadu.

It gave excellent results within five years, and slowly every state took it as role model. Since its implementation, Chennai saw a 50% rise in the water table in five years and the water quality significantly improved.