UGC NTA NET/JRF Exam, Environmental Sciences, September-2022

Total Questions: 100

61. Given below are two statements.

Statement I: Noise pollution exists in the form of energy and is highly subjective in nature unlike air pollution.

Statement II: Noise pollution exists irrespective of loudness of sound and causes both physiological and psychological stress among individual or group of individuals.
In light of the above statements, choose the correct answer from the options given below:

Correct Answer: A. Both Statement I and Statement II are true
Solution:

Noise pollution, or sound pollution, is the propagation of noise or sound with ranging impacts on the activity of human or animal life, most of which are harmful to a degree.

High noise levels can contribute to cardiovascular effects in humans and an increased incidence of coronary artery disease.

In animals, noise can increase the risk of death by altering predator or prey detection and avoidance, interfere with reproduction and navigation, and contribute to permanent hearing loss.

Noise pollution exists irrespective of loudness of sound and causes both physiological and psychological stress among individual or group of individuals.

62. Given below are two statements about Baghouse filter used to control air pollution.

Statement I: Baghouse filters are fabric bag filter which can be repeatedly cleaned and reused. Collection efficiency can be very high (99.9% for all size of particles).

Statement II: Collection efficiency of baghouse filters decreases as dust collected on filters and lead to decrease in pressure drop which increases airflow or decreases cost of forcing air through filters.

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

Correct Answer: C. Statement I is true, but Statement II is false
Solution:

A baghouse filter or fabric filter is a kind of air pollution control device which is used to collect particulates out of gasses released by commercial process gases.

This air-material separator performs well in a relatively small loading of particles. These types of filters have a high dust collection efficiency, which depending on the type of dust is up to 99.9% efficiency.

63. Given below are two statements.

Statement I: An incineration process used to destroy highly toxic and hazardous waste differs from the municipal solid waste incineration process.

Statement II: Incineration emits small but significant amounts of numerous toxic chemicals and produces ash residues (bottom and flyash) which must be buried in approved landfills.
In light of the above statements, choose the correct answer from the options given below:

Correct Answer: A. Both Statement I and Statement II are true
Solution:

Incineration is a waste treatment process that involves the combustion of substances contained in waste materials. Incinerators reduce the solid mass of the original waste by 80-85% and the volume (already compressed somewhat in garbage trucks) by 95-96%, depending on composition and degree of recovery of materials such as metals from the ash for recycling.

Incineration has particularly strong benefits for the treatment of certain waste types in niche areas such as clinical wastes and certain hazardous wastes where pathogens and toxins can be destroyed by high temperatures.

Examples include chemical multi-product plants with diverse toxic or very toxic wastewater streams, which cannot be routed to a conventional wastewater treatment plant.

64. Given below are two statements.

Statement I: Student t-test is a nonparametric test.
Statement II: Paired t-test compares the two correlated sample means.
In light of the above statements, choose the correct answer from the options given below:

Correct Answer: D. Statement I is false, but Statement II is true
Solution:

A paired 1-test (also known as a dependent or correlated t-test) is a statistical test that compares the averages/means and standard deviations of two related groups to determine if there is a significant difference between the two groups.

T tests are a type of parametric method; they can be used when the samples satisfy the conditions of normality, equal variance, and independence.

65. Which of the following compounds in dirty dozens' list of POPs are formed as byproduct of other compounds and not applied directly in environment?

(a) DDT
(b) Dioxins
(c) Неxаchlorobenzene
(d) Fu
(e) Heptachlor
Choose the correct answer from the options given below:

Correct Answer: B. (b) and (d) only
Solution:

In 1995, the United Nations Environment Programme expanded its research and investigation on POPs with an initial focus on what became known as the "Dirty Dozen".

These were a group of 12 highly persistent and toxic chemicals: aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzen, mirex, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and toxaphen.

Many of the pesticides in this group are no longer used for agricultural purposes but a few continue to be used in developing countries.

66. Which of the following is correct for AAS?

(a) It can only analyze single element at a time.
(b) It has low linear dynamic range.
(c) It can analyze Hg in vapor phase.
(d) It can analyze arsenic in hydride form.
(e) It works on principle of Beer Lambert's law.
Choose the correct answer from the options given below:

Correct Answer: C. (a), (b), (c), (d) and (e)
Solution:

Atomic Absorption Spectroscopy is an instrumental analysis technique for rapid trace metal analysis. It is based on element specific wavelength light absorption by ground state atoms in the flame or electrothermal graphite furnace.

Typical applications of AAS include:
• Quantitative metal concentrations in solution
• Analysis of lead in paint Monitoring of trace metals in industrial effluent streams
• Trace elements in product/raw materials along with ICP-MS
• Analysis of additives and purity in steels and other metal alloys
• Analysis of low-level contaminants

67. The individual plant populations have following group characteristics:

(a) Density
(b) Age
(c) Ratios
(d) Natality
(e) Dominance
Choose the correct answer from the options given below:

Correct Answer: A. (a), (b), (c) and (d) only
Solution:

Populations have some features that, as an organism, a species lacks. Following are the different attributes of a population.
1. Birth and Death Rates
2. Sex Ratio
3. Age Distribution
4. Population Density

Birth and Death Rates: These attributes could be statistically measured for a population, but not for an organism. This is because an organism has birth and death, but not birth rate and death rate.

Sex Ratio: The sex ratio calculates the ratio of male to female individuals in a population.

Age Distribution: The next population attribute is age distribution. A population comprises different age groups such as prereproductive, reproductive and postreproductive age groups.

This age distribution is graphically represented by an age pyramid. The age pyramid indicates whether a population is growing, stable or declining.

Population Density: Population density tells the size of a population. This attribute is the reflection of the condition of a habitat. More density indicates that the habitat provides more favourable living conditions.

68. In the layered structure of the Earth, mantle is mostly made up of:

(a) Na and K
(b) Mg and Fe
(c) Ni
(d) Si
(e) Al
Choose the correct answer from the options given below:

Correct Answer: C. (b) and (d) only
Solution:

In terms of its constituent elements, the mantle is made up of 44.8% oxygen, 21.5% silicon, and 22.8% magnesium.

There's also iron, aluminum, calcium, sodium, and potassium. These elements are all bound together in the form of silicate rocks, all of which take the form of oxides.

69. Which of the following is not true about Solar Energy?

(a) It has low environmental impact.
(b) It is intermittent in its availability and requires efficient storage for continuous power supply.
(c) Receives high regulatory credit from government in recognition of low amount of air pollution and GHG emission.
(d) It has low operating cost.
(e) It provides low density of energy per unit collection surface area.
Choose the correct answer from the options given below:

Correct Answer: C. (c) only
Solution:

With the growing threat of climate change due to the excessive release of carbon emissions, many nations are looking to clean energy alternatives to replace traditional fossil fuels.

Of all the clean energy alternatives, solar has arguably been the most expensive though prices have been declining.
• Solar energy is becoming an increasingly cost-competitive alternative to fossil fuels.
• Solar energy is a sustainable energy source, has a low environmental impact, and promotes energy independence.
• On the other hand, it is limited by how long the sun is out, may cause a scarcity of materials, and contains hazardous materials similar to electronics.
• Pricey disadvantages of solar energy may be rendered negligible by technological advances that increase efficiency and storage capacity.
• Increasing the incentives for the development of solar energy may be worthwhile.

70. Deep open Benthos Communities:

(a) extend from the boundary of continental shelf to the deepest oceans.
(b) often are entirely heterotrophic living on and in mud surface and bacteria.
(c) include plankton and large swimming animals.
(d) are rich in biodiversity through strange, occupying permanent cold and dark water. (e) are nutrient rich water supporting growth of organisms.
Choose the correct answer from the options given below:

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

Biota of Benthic zone: It extends from boundary of continental shelf to the deepest oceans. Since there is no light, plants are absent and only heterotrophic communities are present which live on in the mud surface and bacteria.

The deep benthic zone is rich in diversity though strange, occupying cold and dark space surviving under intense pressure and scarcity of food.