UGC NTA NET/JRF Exam, Environmental Sciences, March-2023

Tonalite and Actinolite are not considered thorium minerals. Monazite and Thorite, on the other hand, are primary sources of thorium. Monazite is a phosphate mineral that contains thorium, cerium, and other rare earth elements.

Thorite, as its name suggests, is primarily a thorium silicate mineral. Tonalite is an igneous, plutonic (intrusive) rock, with phaneritic texture. Actinolite is a member of the amphibole group of silicate minerals.

While thorium can be found in various minerals, it is primarily extracted from Monazite and Thorite due to their higher thorium concentrations.

Sandstone and Limestone are common hydrocarbon reservoir rocks. Reservoir rocks are porous and permeable, allowing them to store and transmit hydrocarbons.

Sandstone is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains, often having good porosity and permeability.

Limestone, a carbonate sedimentary rock, can also have the requisite porosity and permeability to act as a reservoir.

On the other hand, Shale and Mudstone, being fine-grained sedimentary rocks, typically act as cap rocks or barriers to fluid flow because of their low permeability.

Acidity in soils can be introduced or exacerbated by several factors. The presence of soluble aluminum can increase soil acidity as aluminum becomes more soluble under acidic conditions.

Mine tailing deposits can lead to acid mine drainage, introducing acidity to surrounding soils. Emissions from thermal power plants often contain sulfur oxides that can lead to acid rain, acidifying soils.

Leaching of basic cations can decrease the soil's buffering capacity, making it more susceptible to acidification. However, leaching of Si from silicate minerals does not directly introduce acidity.

Instead, it's the dissolution of silicates and the associated release of cations like calcium and magnesium that can affect soil pH.

Control of particulate matter in the ambient atmosphere is crucial for environmental health. Bag houses, or fabric filters, capture particulates by forcing air through fabric.

Cyclone collectors use centrifugal force to separate particles from the air. Electrostatic precipitators use electric fields to trap and remove particles.

Among the options, the Limestone injection multistage burner (LIMB) is more related to controlling sulfur dioxide emissions from coal-fired power plants, while catalytic converters are used in vehicles to reduce harmful emissions of nitrogen oxides, carbon monoxide, and hydrocarbons.

Thus, the primary techniques for controlling particulate matter are Bag houses, Cyclone collectors, and Electrostatic precipitators.

The correct statements among the given options are that an increase in temperature reduces dissolved oxygen (DO) in lake water, agricultural run-off can introduce turbidity, enrichment of nutrients can speed up lake aging, and both atmospheric exchange and photosynthesis can introduce DO to lake water.

Elevated temperatures reduce the solubility of oxygen, leading to reduced DO levels in water bodies. Agricultural run-off often carries with it suspended sediments, which causes turbidity.

Nutrient enrichment, or eutrophication, accelerates the aging of lakes, leading to increased productivity and eventually a dominance of vegetation.

This can lead to hypoxic or anoxic conditions, which are harmful to many aquatic organisms. Lastly, the primary sources of DO in water bodies are the atmosphere (via diffusion) and photosynthesis by aquatic plants and algae.

The Environment (Protection) Act, 1986, was enacted to provide for the protection and improvement of the environment.

Its objectives include the prevention of hazards to all living creatures and property, conservation of natural heritage, and maintaining a harmonious relationship between humans and their environment.

Checking soil erosion and increasing the productivity of forests are not direct objectives of this Act, although they may be outcomes of some of its provisions.

Mukundara Hills Tiger Reserve and Shergarh Wildlife Sanctuary are both located in the state of Rajasthan. The reintroduction of cheetahs in India has been a topic of discussion for many years.

These sites have been evaluated and found to be suitable habitats for cheetah reintroduction due to their vast landscapes, prey base, and minimal human-animal conflict.

The other sites mentioned, like Gandhi Sagar Wildlife Sanctuary and Madhav National Park, are located in Madhya Pradesh, and Nauradehi Wildlife Sanctuary is in Madhya Pradesh and Chhattisgarh.