Natural Resources Questions and Answers

Answer: B

The Mohs scale has 10 minerals.

Friedrich Mohs defined it in 1812 as a ranking by scratch resistance, each mineral scratching those below it: 1 talc, 2 gypsum, 3 calcite, 4 fluorite, 5 apatite, 6 orthoclase, 7 quartz, 8 topaz, 9 corundum and 10 diamond.

The scale is ordinal, not proportional: diamond is far more than ten times as hard as talc, and the gap between corundum and diamond is the largest of all. It has neither 8, 12 nor 15 reference minerals.

Answer: A

Energy released at the source is measured on the Richter scale.

Charles Richter's local magnitude scale of 1935 is logarithmic: each whole number step means ten times the ground-motion amplitude and about 32 times more energy released. Magnitude is a single figure for the earthquake itself. Modern agencies mostly use the related moment magnitude, but the principle is the same.

The Mercalli scale measures intensity, the observed effects and damage at a particular place, which varies with distance from the epicentre. Mohs' scale ranks mineral hardness. 'Levis' is not a seismic scale.

Answer: B

An individual house owner can adopt Roof top rainwater harvesting.

Rain falling on the roof is led through gutters and pipes, past a first-flush device and a simple filter, into a storage tank or a recharge pit or well. It needs only the house's own roof and a small plot, and many cities, Chennai among them, have made it compulsory for new buildings.

Creating a new water body, digging recharge trenches across a catchment and building large storage tanks are community or government works that need land, funds and planning beyond one household.

Answer: B

Red soil gets its colour from Iron.

Red soils develop on old crystalline and metamorphic rocks such as granite and gneiss in areas of low to moderate rainfall, across Tamil Nadu, Karnataka, Andhra Pradesh, Odisha and Jharkhand. Iron released by weathering is oxidised and spread through the soil as ferric oxide, which gives the red colour; where the iron is hydrated the soil looks yellow.

Magnesium and aluminium compounds are pale, and copper is not present in amounts that could colour a whole soil type.

Answer: C

A quarry is an open pit for rock mining.

Quarrying extracts building stone, limestone, granite, sand or gravel from an open excavation at the surface. It is a type of surface mining, but the word is used for rock and stone, not coal.

An open coal mine is an opencast mine, and an underground coal mine works coal seams through shafts and galleries. Explosives may be used in quarrying, but 'explosive mine' describes a weapon, not a quarry.

Answer: B

Energy conservation is expressed by the first law of thermodynamics.

The first law states that energy can be neither created nor destroyed, only converted from one form to another. For a closed system the change in internal energy equals the heat added minus the work done by the system:

\[ \Delta U = Q - W \]

The zeroth law defines thermal equilibrium and temperature, the second law concerns entropy and the direction of natural processes, and the third law concerns entropy as temperature approaches absolute zero.

Answer: C

The one-element material is diamond.

Diamond is pure carbon, a single element with every atom bonded to four others in a tetrahedral network.

Rock is an aggregate of minerals, sand is mostly silica (SiO₂), a compound of silicon and oxygen, and bronze is an alloy of copper and tin.

Answer: D

The Rann of Kutch lies in Zone V.

The Bureau of Indian Standards' seismic zoning map places Kutch in Zone V, the highest-risk zone, alongside the Himalaya, the North-East and the Andaman and Nicobar Islands. The 1819 Rann of Kutch earthquake and the 2001 Bhuj earthquake both struck this region.

Zones II, III and IV carry progressively less risk, and most of peninsular India lies in them.

Answer: D

Gondwana coal is mined at Raniganj.

The Raniganj coalfield in West Bengal lies in the Damodar valley Gondwana basin and was the first coalfield worked in India, from 1774. The Gondwana basins supply most of India's coal.

Jaduguda in Jharkhand is a uranium mine, Amba Dongar in Gujarat is a carbonatite deposit of fluorite, and Bastar in Chhattisgarh is known for its iron ore.

Answer: D

Fossil fuels are composed mainly of carbon and hydrogen.

Coal, petroleum and natural gas are hydrocarbons or carbon-rich materials formed from buried organic matter. Burning them oxidises the carbon to carbon dioxide and the hydrogen to water, releasing energy.

Nitrogen, oxygen and sulphur occur only in smaller amounts as impurities. Sulphur matters for pollution (it forms SO₂), but it is not a main constituent.