UGC NTA NET/JRF Exam, Environmental Sciences, September-2024

(a) Komatiite (IV) is a high-temperature igneous rock, typically ultramafic and formed by very hot magma flows in the Archean eon.
(b) Granulite (I) is known to be a high-grade metamorphic rock, having been subjected to high temperature and pressure.
(c) Arkose (II) is a clastic sedimentary rock that contains a high percentage of feldspar. (d) Dolomite (III) is a non-clastic sedimentary rock, formed primarily by chemical processes or diagenetic replacement of calcite by magnesium.

(a) ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) (IV) is generally a destructive technique since it requires digesting the sample in liquid form to analyze its elemental composition.
(b) XRD (X-ray Diffraction) (III) is widely used for crystallography, helping to identify the crystal structure of substances.
(c) XRF (X-ray Fluorescence) (I) is a nondestructive method for elemental analysis, often used on solid samples directly.
(d) UV-VIS (II) is employed in colorimetric or spectrophotometric techniques to quantify elements or compounds based on absorption in the ultraviolet and visible regions.

Different fractions of municipal solid waste and fossil-fuel derivatives have characteristic Higher Heating Values (HHV). Generally, green yard waste (e) has the lowest HHV because of high moisture content (often in the range of 6,000-10,000 kJ/kg).

Mixed paper (a) is typically next, with HHV around 13,000-15,000 kJ/kg. Leather (d) often reaches around 15,000- 18,000 kJ/kg. Rubber (b) can go above 25,000 kJ/kg, and mixed plastics (c) typically exhibit even higher values, frequently above 30,000 kJ/kg.

Hence the ascending order is (e)→ (a)→ (d)→ (b)→ (c).

Monazite is a phosphate mineral containing thorium and rare earth elements. It occurs in beach sands, especially along the coasts of India and other countries.

Because of its significant thorium content, monazite can be processed to extract thorium, which can serve as an atomic fuel in certain nuclear reactor designs.

Pitchblende is a principal ore of uranium, apatite is a phosphate mineral unrelated to thorium fuel, and malachite is a copper carbonate mineral.

The extinction vortex in a small population is driven by the following processes:

(b) Inbreeding and genetic drift, which occur in small populations, leading to a reduction in genetic diversity.

(c) Loss of genetic variability further diminishes the population's ability to adapt to changing environments.

(d) Lower individual fitness and population adaptability occur due to the loss of genetic diversity and adaptation.

(e) This results in lower reproduction rates and higher mortality rates, which accelerates the decline of the population.

(a) Finally, the smaller population continues to shrink as these processes feed back into one another.
Thus, the correct sequence is (b) → (c) → (d) → (e) → (a).

Nature-based solutions (NBS) are approaches inspired and supported by nature that provide environmental, social, and economic benefits, helping to mitigate climate change impacts, conserve biodiversity, and enhance ecosystem services.

IUCN has been a key international organization to conceptualize and promote NBS, integrating them into global conservation, development, and climate policy agendas.

Recent assessments of wind power potential at 100 m or 120 m hub height (e.g., by the National Institute of Wind Energy, NIWE) indicate that Gujarat has the highest estimated wind energy potential among Indian states.

While Tamil Nadu has historically led in installed capacity, the potential resources at taller turbine hub heights are currently found to be largest in Gujarat, followed by Rajasthan, Tamil Nadu, and others.

The absorbed dose of ionizing radiation in the International System of Units (SI) is measured in Grays (Gy). One gray corresponds to the absorption of one joule of radiation energy per kilogram of matter.

Older units include the rad (1 Gy = 100 rad). Other radiation-related units, such as Roentgen (R) and Becquerel (Bq), measure exposure and radioactivity rather than absorbed dose.