Minerals and Energy Resources

Q1. Haban observes buses and trains moving on roads in Guwahati and asks why his village houses don't move like them. His father explains these vehicles are made of metals like iron and aluminium. Based on the chapter, what is the PRIMARY reason metals are extracted from minerals rather than used directly from rocks?

• A. Metals in rocks are mixed with other elements and need refining to be commercially viable for use ✓
• B. Rocks are too hard and cannot be broken to extract metals
• C. Minerals are found only in urban areas near cities
• D. Metals lose their properties when mixed with rocks

Answer: A — The chapter states that ore is 'an accumulation of any mineral mixed with other elements' and that 'mineral content must be in sufficient concentration to make extraction commercially viable'; rocks contain minerals but require processing, not that rocks are unbreakable or location-dependent.

Q2. A toothpaste manufacturer lists these minerals in their product: silica, fluorite, titanium oxide, and mica. According to the chapter, which of these minerals serves a HEALTH-PROTECTIVE function rather than a cleaning or cosmetic function?

• A. Fluorite (source of fluoride) — reduces cavities ✓
• B. Silica — provides abrasive cleaning action
• C. Mica — gives sparkle to the paste
• D. Titanium oxide — makes toothpaste white

Answer: A — The chapter explicitly states 'Fluoride which is used to reduce cavities, comes from a mineral fluorite,' making it health-protective; silica, mica, and titanium oxide are described as cleaning or cosmetic agents.

Q3. Assertion (A): Coal and iron ore found in sedimentary rocks have been concentrated as a result of long periods under great heat and pressure. Reason (R): Sedimentary minerals are always formed by evaporation in arid regions. Choose the correct option:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false ✓
• D. A is false but R is true

Answer: C — Assertion A is accurate per the chapter; however, Reason R is false because the chapter states sedimentary minerals form through multiple modes—heat/pressure concentration AND evaporation in arid regions (two different processes), not always by evaporation.

Q4. A mining company in Meghalaya wants to extract coal using traditional rat-hole mining methods. According to the chapter's discussion, what is the PRIMARY environmental or regulatory consequence of this practice?

• A. The National Green Tribunal has declared such activities illegal and recommended they be stopped ✓
• B. Rat-hole mining is the most efficient method and is encouraged by the government
• C. Rat-hole mining extracts coal from placer deposits which are renewable
• D. The practice is legal because minerals in tribal areas are owned by individuals or communities

Answer: A — The chapter explicitly states 'The National Green Tribunal has declared such activities illegal and recommended that these should be stopped forthwith'; while individual/community ownership is mentioned, it does not override the tribunal's legal ban.

Q5. Assertion (A): Veins and lodes in igneous and metamorphic rocks are formed when minerals in liquid, molten and gaseous forms are forced upward through cavities towards the earth's surface. Reason (R): Tin, copper, zinc and lead are major metallic minerals obtained from veins and lodes. Choose the correct option:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A ✓
• C. A is true but R is false
• D. A is false but R is true

Answer: B — Both statements are true per the chapter; however, R does not explain WHY A is true—R merely describes WHICH minerals come from veins/lodes, not HOW they form.

Q6. A student reads that 'minerals represent only about 0.3 per cent of total nutrient intake, yet are potent and important.' Which inference about mineral nutrition is BEST supported by this statement from the chapter?

• A. Minerals are more important than carbohydrates, proteins, and fats because they are potent in small quantities
• B. Without minerals, the body cannot utilise the other 99.7 per cent of foodstuffs despite their availability ✓
• C. Mineral deficiency is impossible because they comprise only 0.3 per cent of intake
• D. Minerals should be avoided in diets because they are too potent

Answer: B — The chapter states 'without them we would not be able to utilise the other 99.7 per cent of foodstuffs,' indicating minerals are essential for nutrient utilization despite low percentage; option A contradicts the statement's emphasis on their small proportion, and C/D misinterpret the significance.

Q7. Assertion (A): Bauxite is formed as a result of decomposition of surface rocks and removal of soluble constituents. Reason (R): Bauxite deposits are found only in sedimentary rock formations. Choose the correct option:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false ✓
• D. A is false but R is true

Answer: C — Assertion A is correct per the chapter's description of bauxite formation through weathering; Reason R is false because the chapter discusses bauxite formation as a weathering process (mode iii), separate from sedimentary rock formation.

Q8. Gold, silver, tin and platinum are most commonly found as placer deposits in sands of valley floors. Based on the chapter, what physical property of these minerals makes them suitable for placer deposit formation?

• A. They are not corroded by water and remain stable in alluvial environments ✓
• B. They are highly soluble and concentrate in sedimentary layers
• C. They form veins in igneous rocks that are easily transported downslope
• D. They evaporate and recrystallise in arid valley regions

Answer: A — The chapter explicitly states these minerals are 'generally contain minerals, which are not corroded by water,' making them suitable for alluvial/placer deposits; options B and D describe sedimentary and evaporative processes respectively, not placer deposits.

Q9. A geologist and a geographer both study minerals in a region. According to the chapter, what is the KEY difference in their areas of interest?

• A. The geologist studies distribution of mineral resources and economic activities; the geographer studies mineral formation and composition
• B. The geographer studies minerals as part of the earth's crust for understanding landforms; the geologist focuses on formation, age, and physical-chemical composition ✓
• C. The geologist extracts minerals commercially; the geographer only observes them in nature
• D. Both study the same aspects but use different tools and methods

Answer: B — The chapter clearly states 'Geographers study minerals as part of the earth's crust for a better understanding of landforms' and 'A geologist...is interested in the formation of minerals, their age and physical and chemical composition'; option A reverses their interests.

Q10. Assertion (A): Ocean waters contain vast quantities of minerals, but most are too widely diffused to be of economic significance. Reason (R): Common salt, magnesium and bromine are derived from ocean waters because they are concentrated enough to be economically extracted. Choose the correct option:

• A. Both A and R are true and R is the correct explanation of A ✓
• B. Both A and R are true but R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer: A — Both statements are true per the chapter; R correctly explains A by providing examples of minerals that ARE economically extracted from ocean water because they achieve sufficient concentration, contrasting with 'most' minerals that are too diffused.