DAY – 67 : Insta 75 Days Revision Plan-2026 : Geography Full Syllabus

Answer: (a)

Explanation

Venus, the second planet from the Sun, is one of the most studied celestial bodies due to its extreme environment and its historical association with Earth.

• Statement 1 is correct: Venus is the brightest natural object in Earth’s night sky after the Moon. This high albedo (reflectivity) is primarily due to its permanent, thick blanket of clouds composed mostly of sulfuric acid. These clouds reflect and scatter about 70\% of the sunlight that hits them back into space.
• Statement 2 is correct: Venus is frequently referred to as “Earth’s Twin” or “Earth’s Sister Planet.” This is because the two planets are remarkably similar in several physical characteristics:
  • Size: Venus’s diameter is about 95% of Earth’s.
  • Mass: It has about 81% of Earth’s mass.
  • Composition: Both are terrestrial (rocky) planets with similar internal structures (core, mantle, and crust).
• Statement 3 is incorrect: Venus, along with Mercury, is one of the only two planets in our solar system that has no natural satellites (moons). Furthermore, Venus does not have a ring system. Rings are typically found around the gas and ice giants of the outer solar system.

Answer: (a)

Explanation

Although the Equator receives nearly vertical rays of the sun throughout the year, the highest temperatures and maximum insolation are recorded in the subtropical regions (near the Tropics of Cancer and Capricorn) rather than at the Equator itself.

• Statement (a) is correct: The Equator is a region of intense heating, which causes air to rise (convection). This leads to the formation of towering cumulonimbus clouds and heavy afternoon rainfall almost daily. This persistent cloud cover significantly increases the Earth’s albedo (reflectivity) in the equatorial belt, reflecting a large portion of incoming solar radiation back into space before it can reach the surface.
• In contrast, the tropical/subtropical regions are characterized by sinking air (high pressure), which inhibits cloud formation. These regions have clear skies and dry air, allowing a much higher percentage of solar radiation to reach the surface.

Answer: (d)

Explanation

The Pacific Ring of Fire is a massive 40,000 km horseshoe-shaped belt characterized by high volcanic activity and frequent earthquakes. It is essentially a continuous string of oceanic trenches, volcanic arcs, and plate boundaries surrounding the Pacific Ocean.

• Philippine Plate (1): This is a major boundary on the western edge of the Ring of Fire. Its subduction beneath the Eurasian Plate and interaction with the Pacific Plate created the Philippine Trench and the volcanic islands of the Philippines.
• Cocos Plate (2): Located off the coast of Central America, this young oceanic plate is subducting beneath the North American and Caribbean plates. This movement is responsible for the Central America Volcanic Arc.
• Eurasian Plate (3): The eastern edge of the Eurasian Plate interacts with several plates (Pacific, Philippine, etc.) along the western Pacific. This interaction creates the intense seismic and volcanic zones of Japan, the Kuril Islands, and Kamchatka.
• Nazca Plate (4): This is one of the most active sections of the Ring of Fire. The subduction of the Nazca Plate beneath the South American Plate formed the Andes Mountains (the world’s longest continental mountain range) and the deep Peru-Chile Trench.

Answer: (c)

Explanation

Planetary winds (also known as permanent or prevailing winds) are large-scale wind systems that blow throughout the year across the globe in response to the permanent pressure belts created by Earth’s rotation and solar heating.

• Statement 1 is correct: By definition, all winds blow from areas of high pressure to areas of low pressure. Planetary winds are characterized by their permanence; they maintain a consistent direction and path over vast regions of the Earth’s surface (e.g., Trade winds, Westerlies, and Polar Easterlies).
• Statement 2 is incorrect: Winds always blow from high pressure to low pressure. Therefore, Polar Easterlies blow from the Polar High-pressure belts (at the poles) toward the Sub-polar Low-pressure belts (around 60° latitude). The statement incorrectly reverses the direction of flow.
• Statement 3 is correct: In the Southern Hemisphere, air moves from the Sub-tropical High-pressure belt (near 30°S) toward the Equatorial Low-pressure belt. Due to the Coriolis effect, these winds are deflected to the left of their path, resulting in a South-Easterly direction. Hence, they are known as the South-East Trade Winds.

The Coriolis Effect

• Ferrel’s Law: This law states that any object moving on Earth is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
• This is the reason why Trade winds are not simply “North” or “South” winds, but instead acquire their “Easterly” component.

Answer: (c)

Explanation

Ocean currents are large-scale movements of water caused by winds, the Coriolis effect, and differences in water density. They are categorized based on the region and the ocean basin they occupy.

• Pair 1 is correctly matched: The Oyashio Current (also known as the Kurile Current) is a cold sub-arctic ocean current that flows southward in the North Pacific Ocean. It originates in the Arctic Ocean and flows along the eastern coast of Kamchatka and the Kuril Islands to meet the warm Kuroshio Current off the coast of Japan.
• Pair 2 is correctly matched: The Benguela Current is a cold, broad, and slow-moving current that flows northward along the west coast of southern Africa. It is a major component of the South Atlantic Ocean gyre and is famous for the intense “upwelling” of nutrient-rich cold water it causes.
• Pair 3 is correctly matched: The Peruvian Current (famously known as the Humboldt Current) is a major cold current that flows north along the western coast of South America in the Pacific Ocean. It is one of the most productive marine ecosystems in the world and is a key driver of the El Niño-Southern Oscillation (ENSO) cycles.

Answer: (b)

Explanation:
The distribution of temperature and insolation is influenced by the differential heating of land and water, the Earth’s axial tilt, and atmospheric conditions.

Statement 1 is incorrect: The thermal equator, which is an imaginary line joining places having the highest average temperature, does not perfectly coincide with the geographic Equator. Since land heats up more quickly than water, the thermal equator shifts northward during the Northern Hemisphere summer and moves slightly southward during winter. However, it mostly remains in the Northern Hemisphere due to the larger landmass there.

Statement 2 is incorrect: At the top of the atmosphere, both the Northern and Southern Hemispheres receive nearly equal amounts of annual solar insolation. Although the Earth is slightly closer to the Sun in January and farther away in July, the change in Earth’s orbital speed helps balance the annual energy received by both hemispheres.

Statement 3 is correct: Land has a lower specific heat capacity than water, so it heats and cools faster than oceans. Therefore, land-dominated areas experience greater daily and annual temperature variation than water-dominated regions, which remain comparatively more thermally stable.

Answer: (c)

Explanation

The Indian Himalayas are home to thousands of glaciers, predominantly located in the states of Uttarakhand, Himachal Pradesh, and the Union Territories of Ladakh and Jammu & Kashmir.

• Nanda Devi Glacier (1): This is a prominent glacier located in the Chamoli district of Uttarakhand. It is situated within the Nanda Devi Biosphere Reserve and feeds the Rishiganga river.
• Nubra Glacier (2): This glacier is located in the Ladakh region. It is a large glacier in the Karakoram Range that feeds the Nubra River, which eventually joins the Shyok River. It is not in Uttarakhand.
• Zemu Glacier (3): This is the largest glacier in the Eastern Himalayas, located at the base of Kangchenjunga in Sikkim. It is the primary source of water for the Teesta River. It is not in Uttarakhand.
• Bandarpunch Glacier (4): This glacier is located in the Uttarkashi district of Uttarakhand. It is a major source for the Yamuna River and is situated in the Garhwal Himalaya.

Key Glaciers in Other Regions

• Siachen Glacier: The longest glacier in the Karakoram Range (Ladakh); often called the “Highest Battlefield in the World.”
• Biafo and Baltoro: Massive glaciers located in the Karakoram (Gilgit-Baltistan).
• Barashigri: The largest glacier in Himachal Pradesh (Lahaul and Spiti region).

Answer: (c)

Explanation

The Himalayas are divided regionally from West to East based on river valleys and distinct geographical features. The section between the Satluj and Kali rivers is generally referred to as the Kumaon or Himachal-Uttarakhand Himalayas.

• Statement 1 is incorrect: The Western Himalayas are more continuous than the Eastern Himalayas. In the East (Sikkim, Bhutan, and Arunachal Pradesh), the Himalayas are characterized by deep, narrow gorges and a very steep rise from the plains. The proximity of the mountains to the sea (Bay of Bengal) results in high rainfall, leading to intense erosion that has “broken” the continuity of the ranges compared to the broader, more longitudinal Western section.
• Statement 2 is correct: Duns (or Doons) are longitudinal structural valleys formed between the Lesser Himalayas (Himachal) and the Shiwaliks. These are a characteristic feature of the Himachal and Uttarakhand Himalayas. Famous examples include Dehra Dun (the largest), Kotli Dun, and Patli Dun.
• Statement 3 is correct: The Himachal-Uttarakhand Himalayas lie approximately between the Ravi River in the west and the Kali River in the east. Duns or Doons, such as Dehra Dun, Kotli Dun and Patli Dun, are characteristic features of this region. The Eastern Himalayas are more dissected by rivers and are not more continuous than the Western Himalayas.

Answer: (d)

Explanation

The onset of the southwest monsoon over Kerala, typically occurring around June 1, is a significant meteorological event, but its timing does not have a linear or deterministic relationship with the performance of the monsoon over the rest of the season or the country.

• Statement 1 is incorrect: There is no direct correlation between the date of the monsoon onset over Kerala and the total quantum of rainfall India receives during the four-month season (June–September). Historical data shows that years with a delayed onset have often resulted in normal or even surplus rainfall, while early onset years have sometimes ended in a deficit. The total rainfall is governed by larger global and regional factors like El Niño/La Niña, the Indian Ocean Dipole (IOD), and the Madden-Julian Oscillation (MJO).
• Statement 2 is incorrect: A delayed onset over Kerala does not invariably delay the advance of the monsoon over the rest of the country. The monsoon’s progress northwards depends on local atmospheric conditions and the strength of the monsoon branches (Arabian Sea and Bay of Bengal). It is possible for the monsoon to arrive late in Kerala but “catch up” and reach Central or North India on or ahead of schedule due to a surge in monsoon strength.

Answer: (c)

Explanation

The demographic profile of India is undergoing a significant transition, characterized by declining fertility rates and a large working-age population.

• Statement 1 is correct: According to the National Family Health Survey-5 (NFHS-5), conducted between 2019–21, India’s Total Fertility Rate (TFR)—the average number of children born to a woman—has declined to 2.0. This is below the replacement level fertility of 2.1 (the level at which a population exactly replaces itself from one generation to the next without migration).
• Statement 2 is correct: A demographic dividend refers to the economic growth potential that can result from shifts in a population’s age structure. This occurs primarily when the working-age population (15–64 years) grows larger than the non-working, dependent population (children under 15 and the elderly over 65). This shift reduces the dependency ratio and increases the potential for higher productivity and savings.

Correct Answer: d

Explanation:

Volume of original cube = 12 × 12 × 12 = 1728 cm³

Volume of each smaller cube = 3 × 3 × 3 = 27 cm³

Number of smaller cubes = 1728 ÷ 27 = 64

Surface area of one smaller cube = 6 × 3 × 3 = 54 cm²

Total surface area = 64 × 54 = 3456 cm²

Correct Answer: c

Explanation:

Let the dimensions be 3x, 2x and x.

Total Surface Area = 2(lb + bh + lh)

= 2[(3x × 2x) + (2x × x) + (3x × x)]

= 2(6x² + 2x² + 3x²)

= 22x²

Given TSA = 88

22x² = 88

x² = 4

x = 2

Dimensions = 6 cm, 4 cm and 2 cm

Volume = 6 × 4 × 2 = 48 cm³

Correct Answer: a

Explanation:

From the graph, the earnings curve of A remains above that of B for most of the years between 2000 and 2010. Hence, the average earnings of A are greater than those of B over the given period.

Correct Answer: c

Explanation:

The graph only shows the trend and approximate variation in the price of the commodity over different years. It does not provide the exact numerical value for the year 1990. From the graph, we can infer that the price in 1990 lies somewhere between ₹10 and ₹20, but its precise value cannot be determined. Therefore, option (c) is the most appropriate answer.

Correct Answer: c

Explanation:

The passage argues that long-distance transportation and excessive food processing create environmental problems such as pollution, wastage, destruction of rain forests, and increased use of packaging and preservation. It also mentions reduced nutritional content and food insecurity. Therefore, consuming locally grown food can be considered environmentally sustainable, supporting Statement 1. Similarly, the food processing industry increases pressure on natural resources through packaging, preservation, transportation, and wastage, supporting Statement 2. Since both statements are directly supported by the ideas expressed in the passage, the correct answer is option (c), i.e., both 1 and 2 are correct.