UGC NTA NET/JRF Exam, Environmental Sciences, June-2021

Total Questions: 41

31. The ash content in coal used in stand-alone thermal power plants in India should not be more than:

Correct Answer: C. 34%
Solution:

The environment ministry has decided that it will no longer regulate the ash-content of coal used by thermal power plants.

In May, 2020, the ministry issued a notification that overturned its January 2014 regulation that made it mandatory for all coal-based power plants located 500 kilometers or more from the pit-head or coal mine to use raw or blended or beneficiated coal with no more than 34 per cent ash content.

32. Pyrolysis of solid wastes refers to:

Correct Answer: B. High temperature anaerobic distillation
Solution:

Pyrolysis is the thermochemical decomposition of organic material at high temperature and in the absence of oxygen or in an atmosphere of inert gases.

Pyrolysis process consists of both simultaneous and successive reactions when carbon-rich organic material is heated in a non-reactive atmosphere.

Simply speaking, pyrolysis is the thermal degradation of organic materials in the absence of oxygen. Thermal decomposition of organic components in the waste stream starts at 350°C - 550°C and goes up to 700°C - 800°C in the absence of air/oxygen.

33. Which of the following mixture of gases can be found in biogas?

Correct Answer: B. CO₂, CH₄, NH₃, H₂S, H₂O vapour
Solution:

34. India became a party to CITES in the year:

Correct Answer: B. 1976
Solution:

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international agreement to which States and regional economic integration organizations adhere voluntarily.

CITES entered into force in July 1975. Currently there are 183 Parties (include countries or regional economic integration organizations).

India is one of the recognized mega-diverse countries of the world, harbouring nearly 7-8% of the recorded species of the world, and representing 4 of the 34 globally identified biodiversity hotspots (Himalaya, Indo-Burma, Western Ghats and Sri Lanka, Sundaland).

India is also a vast repository of traditional knowledge associated with biological resources. So far, over 91,200 species of animals and 45,500 species of plants have been documented in the ten biogeographic regions of the country.

Inventories of floral and faunal diversities are being progressively updated with several new discoveries through the conduct of continuous surveys and exploration.

India, being a CITES Party, actively prohibits the international trade of endangered wild species and several measures are in place to control threats from invasive alien species (e.g. certificates for exports, permits for imports, etc.).

35. Time clocked by an athlete in a 100 m race is an example of which type of variable?

Correct Answer: B. continuous
Solution:

Discrete data is a numerical type of data that includes whole, concrete numbers with specific and fixed data values determined by counting. Continuous data includes complex numbers and varying data values that are measured over a specific time interval. Nominal data is classified without a natural order or rank, whereas ordinal data has a predetermined or natural order.

36. In a class of 13 students, 3 students failed in a test. The marks of 10 students who passed were 6, 9, 4, 8, 7, 6, 5, 6, 7, 5. The median value of marks of all the 13 students is:

Correct Answer: C. 6
Solution:

Arrange the data in descending/ascending order: 4, 5, 5, 6, 6, 6, 7, 7, 8, 9
Median = is the simple average of the n/2ᵗʰ  and the (1n/2 + 1)ᵗʰ terms.

Here n = 10, n/2ᵗʰ = 5ᵗʰ term, (n/2 +1)ᵗʰ = 6ᵗʰ term Average of 5ᵗʰ term and 6ᵗʰ term = Average (6, 6) = 12/2 = 6.

37. The probability that a standard normal variate lies between -∞ and +1 is:

Correct Answer: A. ~0.84
Solution:



38. Population of a city doubled in a span of 20 years. Assuming exponential growth at a constant rate over the given period, the growth rate would have been:

Correct Answer: A. ~3.5%
Solution:

39. Following information is given regarding a one-way ANOVA test: There are 'k' treatments, each having sample size n₁, n₂, n₃, ... nₖ such that the total sample size N = n₁, + n₂, + n₃, + ... + nₖ.

The degrees of freedom for the mean error sum of squares in the test will be:

Correct Answer: D. N-k
Solution:

The degrees of freedom is equal to the sum of the individual degrees of freedom for each sample. Since each sample has degrees of freedom equal to one less than their sample sizes, and there are k samples, the total degrees of freedom are k less than the total sample size: df = N- k.

40. For a regression model, the following information is given:

Unexplained sum of squares = 25
Explained sum of squares = 75
The value of coefficient of determination for this model is:

Correct Answer: D. 0.75
Solution:

Coefficient of Determination (R²)
(R²) = Explained Variation/Total Variation
= 0.75/(0.75 + 0.25)
= 0.75/1
= 0.75.