UGC NTA NET/JRF Exam, Environmental Sciences, June-2020

Total Questions: 100

61. Given below are two statements:

Statement I: Covariance between two variables X and Y determines whether the correlation between them is negative or positive.

Statement II: The product of the standard deviation of two variables X and Y can be both positive or negative.

In light of the above statements, choose the most appropriate answer from the options given below:

A. Both Statement I and Statement II are correct
B. Both Statement I and Statement II are incorrect
C. Statement I is correct, but Statement II is incorrect
D. Statement I is incorrect, but Statement II is correct

Correct Answer: C. Statement I is correct, but Statement II is incorrect

Solution:

Covariance measures the directional relationship between the returns on two assets. The covariance values of the variable can lie anywhere between -∞ to +∞.

A negative value indicates a negative relationship whereas a positive value indicates a positive relationship between the variables. When the covariance value is zero, it indicates that there is no relationship between the variables.

62. Consider the following statements regarding skewness:

(a) For a positively skewed distribution, the value of the mean is the greatest among the mean, median and mode.
(b) For a negatively skewed distribution, the median is greater than the mean. (c) Karl Pearson's coefficient of skewness always lies between the limits ±1.
(d) Bowley's coefficient of skewness always lies between the limits ±1.
Choose the correct answer from the options given below

A. (a), (b) and (c) only
B. (b), (c) and (d) only
C. (a), (c), and (d) only
D. (a), (b) and (d) only

Correct Answer: C. (a), (c), and (d) only

Solution:

Positive Skewness: A distribution in which more than half of the area under the curve is to be the right side of the mode, is a positively skewed distribution.

The curve of this typе of distribution have their right side more spread than the left one. This skewness is sometimes called skewed to the right.

Thus, in a positively skewed distribution, its right tail is longer than left tail. Under such a distribution 'mean' is greater than the 'mode'. It is clear from figure 1.

63. Consider the following statements about normal distribution:

(a) This distribution is applicable to continuous random variables.
(b) It is a symmetrical distribution.
(c) The mean of a standard normal distribution is 1.
(d) The standard deviation of the standard normal distribution is 1.
Choose the correct answer from the options given below:

A. (a), (b) and (c) only
B. (b), (c) and (d) only
C. (a), (b) and (d) only
D. (a), (c) and (d) only

Correct Answer: C. (a), (b) and (d) only

Solution:

A normal distribution serves as a goop approximation to the distributions of a large number of continuous random variables. It is both continuous and symmetrical. The normal distribution is dependent upon its mean (μ) and its standard deviation (σ).

The standard normal distribution is a normal distribution with a mean of zero and standard deviation of 1. The standard normal distribution is centered at zero and the degree to which a given measurement deviates from the mean is given by the standard deviation.

64. Consider the following statements pertaining to sampling theory:

(a) The standard deviation of the sampling distribution of a statistic is known as its standard error.
(b) The precision of the sample estimate of some population parameter is the reciprocal of the standard error of the sampling distribution of the estimate.
(c) A Type-I error in hypothesis testing occurs when we accept a wrong null hypothesis. (d) A Type-II error in hypothesis testing occurs when we reject a true null hypothesis.
Choose the correct answer from the options given below

A. (a) and (b) only
B. (b) and (c) only
C. (a) and (c) only
D. (c) and (d) only

Correct Answer: A. (a) and (b) only

Solution:

The standard error (SE) of a statistic is the approximate standard deviation of a statistical sample population.

The standard error is a statistical term that measures the accuracy with which a sample distribution represents a population by using standard deviation.

The precision of the sample estimate of some population parameter is the reciprocal of the standard error of the sampling distribution of the estimate.

65. Match List-I (Instrument) with List-II (Function).

List-I (Instrument)	List-II (Function)
(a) Campbell-Stokes Recorder	(i) To measure the visible light flux
(b) Pyrheliometer	(ii) To measure total solar irradiance on a plain surface
(c) Pyranometer	(iii) To measure direct beam solar irradiance
(d) Lux meter	(iv) To measure the sunshine duration

Choose the correct answer from the options given below:
Codes:

	(a)	(b)	(c)	(d)
A.	(i)	(iii)	(ii)	(iv)
B.	(i)	(ii)	(iii)	(iv)
C.	(iv)	(iii)	(ii)	(i)
D.	(iv)	(i)	(ii)	(iii)

Correct Answer: C.

Solution:

(i) A Campbell-Stokes sunshine recorder concentrates sunlight through a glass sphere onto a recording card placed at its focal point. The length of the burn trace left on the card represents the sunshine duration.

(ii) A pyrheliometer is used to measure direct solar radiation from the sun and its marginal periphery. To measure direct solar radiation correctly, its receiving surface must be arranged to be normal to the solar direction.

(iii) A pyranometer is used to measure global solar radiation falling on a horizontal surface. Its sensor has a horizontal radiation-sensing surface that absorbs solar radiation energy from the whole sky (i.e. a solid angle of 2π sr) and transforms this energy into heat.

(iv) Lighting professionals use a light meter (also called an illuminance meter or lux meter) to measure the amount of light in a space/on a particular work surface. The light meter has a sensor that measures the light falling on it and provides the user with a measurable illuminance reading.

66. Match List-I (Analysis) with List-II (Analytical techniques).

List-I (Analysis)	List-II (Analytical techniques)
(a) To analyze organic compounds of pollutants	(i) SEM
(b) To analyze the elemental composition of pollutants	(ii) XRD
(c) Morphological analysis of pollutants	(iii) FTIR
(d) To analyze crystalline materials of pollutants	(iv) XRF

Choose the correct answer from the options given below:
Codes:

Option	(a)	(b)	(c)	(d)
A	(iii)	(ii)	(iv)	(i)
B	(iv)	(iii)	(i)	(ii)
C	(iii)	(iv)	(i)	(ii)
D	(iv)	(iii)	(ii)	(i)

Correct Answer: C.

Solution:

(i) Fourier Transform Infrared (FTIR) Spectroscopy is used to perform qualitative and quantitative analysis of organic compounds and to determines the chemical structure of many inorganic compounds.

(ii) Filters are measured by means of X-ray Fluorescence (XRF) based technique such as micro-XRF and grazing incidence XRF using synchrotron radiation, Mo or W excitation sources, after applying an automatized sample preparation method.

(iii) The use of Scanning Electron Microscope (SEM) has found application in the field of particulate air pollution for several years; its use has helped the study of particle morphology and single particles chemical composition.

(iv) XRD analysis can investigate crystalline material structure, including atomic arrangement, crystallite size, and imperfections.

67. Match List-I (Organism) with List-II (Ecosystem structure components).

List-I (Organism)	List-II (Ecosystem structure components)
(a) Earthworms	(i) Producer
(b) Grass	(ii) Secondary carnivore
(c) Frogs	(iii) Primary carnivore
(d) Hawks	(iv) Detrivore

Choose the correct answer from the options given below.
Codes:

Option	(a)	(b)	(c)	(d)
A	(iv)	(i)	(ii)	(iii)
B	(ii)	(iii)	(iv)	(i)
C	(iii)	(iv)	(i)	(ii)
D	(iv)	(i)	(iii)	(ii)

Correct Answer: D.

Solution:

1. Primary producers are photosynthesizing organisms (the plants); which support the rest of the food chain.

2. Primary consumers are also called herbivores (eat plants); they eat the primary producers. Consumers cannot carry out photosynthesis and get their nutrients and energy by eating other things.

3. Secondary consumers eat the primary consumers, tertiary consumers eat the secondary consumers, and so on. They are all called carnivores because they eat meat. Omnivores eat both plants and meat. Scavengers, like vultures, consume animals that are already dead,

4. Detritivores, such as worms and ants, consume detritus (litter, debris and dung).

5. Decomposers, such as fungi and bacteria, complete the final breakdown of organic matter and return nutrient to the soil to fertilize the producers.

68. Match List I (Elements) with List II (Characteristics).

List-I (Elements)	List-II (Characteristics)
(a) Lithophile	(i) Occur mainly as sulfides
(b) Chalcophile	(ii) Gaseous elements do not generally form compounds
(c) Siderophile	(iii) Occur mainly in oxygen compounds
(d) Atmophile	(iv) Occur mainly as native elements

Choose the correct answer from the options given below:
Codes:

Option	(a)	(b)	(c)	(d)
A	(i)	(ii)	(iii)	(iv)
B	(i)	(iv)	(iii)	(ii)
C	(iii)	(iv)	(i)	(ii)
D	(iii)	(i)	(iv)	(ii)

Correct Answer: D.

Solution:

Lithophile, siderophile and chalcophile refer to the tendency of the element to partition into a silicate, metal, or sulfide liquid respectively. Lithophile elements are those showing an affinity for silicate phases and are concentrated in the silicate portion (crust and mantle) of the earth.

Siderophile elements have an affinity for a metallic liquid phase. They are depleted in the silicate portion of the earth and presumably concentrated in the core.

Chalcophile elements have an affinity for a sulfide liquid phase. They are also depleted in the silicate earth and may be concentrated in the core.

Atmophile elements are generally extremely volatile (i.e., they form gases or liquids at the surface of the Earth) and are concentrated in the atmosphere and hydrosphere.

69. Match List-I (Rock types) with List-II (Characteristics)

List-I (Rock types)	List-II (Characteristics)
(a) Rudaceous	(i) Rocks consisting mainly of silt and siltstones
(b) Arenaceous	(ii) Rocks consisting mainly of gravels, pebbles, cobbles, and boulders
(c) Silt rocks	(iii) Rocks consisting mainly of dust, mud, and clay
(d) Argillaceous	(iv) Rocks consisting mainly of sands

Choose the correct answer from the options given below:
Codes:

	(a)	(b)	(c)	(d)
A.	(ii)	(i)	(iv)	(iii)
B.	(iv)	(ii)	(i)	(iii)
C.	(iv)	(i)	(iii)	(ii)
D.	(ii)	(iv)	(i)	(iii)

Correct Answer: D.

Solution:

The factor of grade size is the one most used for the classification of sedimentary rocks. Four groups may be distinguished:

1. Rudaceous: Rocks consisting chiefly of gravel, pebbles, cobbles, or boulders. Loose materials of this class are gravels, pebblebeds, shingle, boulder-beds, scree, talus, etc. When cemented they form conglomerates and breccias.

2. Arenaceous: Rocks consisting chiefly of material of sand grade. Loose materials are sands; when consolidated they form sandstones, grits, arkoses, graywackes, etc.

3. Silt Rocks: Rocks consisting chiefly of material of silt grade. Silt and siltstones. This class is usually included either with the arenaceous or the argillaceous classes, but several distinct rock types occur in it, and the group is worthy of a separate designation.

4. Argillaceous: The clay rocks, consisting of the finest materials of rock decay. Dust, mud, clay, when more or less unconsolidated; mudstone and shale when compacted.