CBSE Class 11 Geography Question Paper Set 07 with Solutions

Answer: (b) Estuary. An estuary forms where a river meets the sea, and the Indian Desert has no such feature; mushroom rocks, shifting dunes (barchans) and oases are typical desert features.

Teacher's Note:
1. Link each landform with its geomorphic agent: wind and arid conditions give mushroom rocks and dunes.
2. Estuaries belong to coasts and river mouths, so they are easy to eliminate.

Answer: (a) Both i and ii are correct. Rotation produces the pole-fleeing (centrifugal) force, which is strongest at the equator and makes it bulge, so the earth is a geoid (flattened at the poles).

Teacher's Note:
1. Rotation causes the pole-fleeing force and so the equatorial bulge.
2. Do not confuse this force with gravity, which pulls matter toward the centre.

Answer: (a) The hypocentre (focus) is the point within the crust where the energy is released and seismic waves originate. The point on the surface nearest to it is the epicentre.

Teacher's Note:
1. Focus and hypocentre mean the same thing; epicentre is the surface point above it.
2. Remember that damage is greatest near the epicentre, as it is closest to the focus.

Answer: (d) 80 km. The mesosphere lies above the stratosphere (which ends at about 50 km) and extends up to about 80 km, where temperature falls to about −100°C.

Teacher's Note:
1. Layers in order: troposphere, stratosphere, mesosphere, thermosphere, exosphere.
2. The mesosphere is the coldest layer, which helps you remember it.

Answer: (b) Crust and upper mantle. The rigid outer layer made of the crust and the uppermost part of the mantle is the lithosphere, about 10 to 200 km thick.

Teacher's Note:
1. Lithosphere is a rigid mechanical layer and not the same as the crust alone.
2. The softer layer below it is the asthenosphere.

Answer: (d) Anticlockwise. In the northern hemisphere the Coriolis force deflects winds to the right, so air spirals inward around a low (cyclone) in an anticlockwise direction.

Teacher's Note:
1. Low pressure in the northern hemisphere means anticlockwise, high pressure means clockwise.
2. The directions reverse in the southern hemisphere.

Answer: (d) Coriolis cell. Polar, Hadley and Ferrel cells are the three circulation cells of the general atmospheric circulation; the Coriolis is a force (due to rotation), not a cell.

Teacher's Note:
1. Coriolis is a force and not a circulation cell.
2. The three cells are named by latitude: Hadley (tropics), Ferrel (mid-latitudes), Polar.

Answer: (c) Arctic Plate. The Pacific, Nazca and Antarctic plates are major or minor plates; there is no Arctic plate.

Teacher's Note:
1. Learn the list of major plates: Pacific, North American, South American, African, Eurasian, Indo-Australian, Antarctic.
2. Nazca is a minor plate off the west coast of South America.

Answer: (c) Duars. The Northern Plains are divided into Bhabar, Tarai, Bhangar (older alluvium) and Khadar (newer alluvium); Duars is a local name for the foothill tract of the Brahmaputra and northern Bengal.

Teacher's Note:
1. Move from the foothills southward: Bhabar, Tarai, Bhangar, Khadar.
2. Khadar is renewed by floods almost every year, so it is very fertile.

Answer: One light year = distance light travels in one year = 365 × 24 × 60 = 525 600 minutes of travel.
Distance = 8.311 light minutes = \( \dfrac{8.311}{525600} \) light years ≈ 1.58 × 10⁻⁵ light years (about 15 crore km).

Teacher's Note:
1. Convert the time to the same unit as a year before dividing.
2. Light years measure distance, not time, even though the word 'year' appears.

Answer: 1 − c, 2 − a, 3 − b, 4 − d. Wind shapes deserts, running water dominates humid tropical regions, glaciers work in high mountains, and tides and waves shape coasts.

Teacher's Note:
1. Think of the main agent that dominates the climate of each area.
2. In deserts, wind erosion is more important than running water.

Answer: A light year is the distance that light travels in one year; it is a unit of astronomical distance. Its value is about 9.46 × 10¹² km (light speed 3 × 10⁵ km/s).

Teacher's Note:
1. Light year is a unit of distance, not time.
2. Mention both the definition and the value to earn full marks.

Answer: Structure; stage. According to W. M. Davis, landforms are a function of structure, process and stage.

Teacher's Note:
1. Davis called this the trio of structure, process and stage.
2. Structure means the rocks and their arrangement, and stage means the time during which processes have acted.

Answer: The greenhouse effect is the warming of the lower atmosphere because gases such as carbon dioxide, methane and water vapour allow incoming shortwave solar radiation to pass but trap outgoing longwave terrestrial radiation, keeping the earth warm enough for life.

Teacher's Note:
1. Say clearly that shortwave energy enters and longwave energy is held back.
2. Do not mix up the natural greenhouse effect with global warming caused by extra gases.

Answer: False. On heating, air expands, so its density decreases and its pressure falls; the first part is true but the second is wrong.

Teacher's Note:
1. Warm air expands and rises, giving low pressure.
2. Cold air is dense and sinks, giving high pressure.

Answer: Jet stream. Jet streams are narrow bands of very strong westerly winds in the upper troposphere.

Teacher's Note:
1. Jet streams blow at heights of about 9 to 14 km.
2. They greatly influence weather, such as the arrival of the monsoon over India.

Answer: (c) Both (a) and (b). The passage says conservation with sustainable use is possible only with the involvement and cooperation of local communities and individuals.

Teacher's Note:
1. Look for the sentence in the passage that contains the key phrase 'local communities and individuals'.
2. Answer from the passage and not from general knowledge.

Answer: (d) Economic rewards to common people. The passage mentions education, reorienting activities and sustainable development, but never economic rewards.

Teacher's Note:
1. In 'not' questions, check each option against the passage.
2. Three options match lines of the passage and one does not.

Answer: (a) Conservation of land. The Act led to national parks and sanctuaries being established and biosphere reserves being declared; land conservation as such is not mentioned.

Teacher's Note:
1. The Act protects wildlife and its habitats within designated areas.
2. Match each option with the last sentence of the passage.

Answer: (c) Both statements are correct. Steps (iv) and (v) of the strategy in the passage say exactly this.

Teacher's Note:
1. Verify each statement separately against the listed steps.
2. Note that the strategy is addressed to each country, not to each person.

Answer: Annual range = highest monthly mean − lowest monthly mean.
1. Station A: 28.7 − 26.2 = 2.5°C.
2. Station B: 34.5 − 14.2 = 20.3°C.

Teacher's Note:
1. Pick the highest and lowest monthly values, not the first and last.
2. A small range suggests a maritime or equatorial place and a large range suggests a continental place.

Answer: 1. Station A: total = 2.3 + 2.1 + 3.7 + 10.6 + 20.8 + 35.6 + 22.5 + 14.6 + 13.8 + 27.3 + 20.6 + 7.5 = 181.4 mm; average = 181.4 ÷ 12 ≈ 15.1 mm per month.
2. Station B: total = 2.1 + 2.4 + 1.3 + 1.0 + 1.0 + 6.8 + 18.6 + 17.0 + 14.0 + 1.4 + 0.2 + 0.9 = 66.7 mm; average = 66.7 ÷ 12 ≈ 5.6 mm per month.

Teacher's Note:
1. Add all twelve months carefully before dividing by 12.
2. Always write the unit (mm) with your answer.

Answer: 1. Station A has an equable, maritime / warm humid climate: its temperature is high throughout the year (26 to 29°C) with a range of only 2.5°C, and rain falls in every month.
2. Station B has an extreme, continental / hot semi-arid climate: its annual range is 20.3°C (14.2°C in January to 34.5°C in June), and it is very dry in most months with rain concentrated in July to September (monsoon-type rain).

Teacher's Note:
1. Judge climate from the range of temperature and the spread of rainfall through the year.
2. Support each conclusion with at least one figure from the table.

Answer: Alfred Wegener's theory of continental drift is supported by these evidences:
1. Matching of continents (jig-saw fit): the coasts of South America and Africa fit closely, especially the Bullard fit made at 1000-fathom depth.
2. Rocks of similar age: marine deposits and rock belts of 2,000-million-year age in Brazil match those in West Africa.
3. Tillite: glacial deposits of the Gondwana system occur in India, Africa, South America, Australia and Antarctica, showing they were once joined near the pole.
4. Placer deposits: the gold-bearing rocks of Ghana have no source in Africa but match the Brazil plateau.
5. Distribution of fossils: Mesosaurus remains occur only in South Africa and Brazil, and Glossopteris flora in several southern continents.

Teacher's Note:
1. Choose any three evidences and explain each in one or two lines with an example.
2. Mention the supercontinent Pangaea or Gondwana to show the idea behind the evidence.

Answer: 1. Latitude: the Tropic of Cancer passes through the middle of India, so the southern half is tropical and the northern half is subtropical, giving high temperatures and a large annual range in the north.
2. Altitude: the Himalayas in the north act as a barrier to cold winds from central Asia and cause monsoon rain; temperature falls with height, so hill stations are cooler than the plains.
3. Pressure and winds: seasonal reversal of winds (southwest and northeast monsoons) brings seasonal rainfall.
4. Distance from the sea / ocean currents: coastal areas have a moderate climate, interior places are extreme.
5. Relief: the Western Ghats cause heavy rain on the windward side and a rain-shadow area on the leeward side.

Teacher's Note:
1. Give three factors with a clear effect for each instead of just naming them.
2. Use Indian examples such as the Himalayas and the Western Ghats.

Answer: 1. Pressure gradient force: the difference in pressure over a distance, shown by closely spaced isobars, causes wind; the closer the isobars, the stronger the wind. It acts at right angles to the isobars.
2. Frictional force: friction with the surface reduces wind speed and is greatest at the surface, becoming negligible above 1 to 3 km; over the sea it is minimal.
3. Coriolis force: due to rotation of the earth, it deflects wind to the right in the northern hemisphere and to the left in the southern hemisphere; it is zero at the equator and greatest at the poles. It changes the direction but not the speed of the wind.

Teacher's Note:
1. The pressure gradient force starts the wind, and the other two forces change its path and speed.
2. Say which force changes direction and which changes speed.

Answer: Composition:
1. The atmosphere consists of gases, water vapour and dust particles.
2. Nitrogen is about 78%, oxygen about 21%, argon about 0.93%, carbon dioxide about 0.03%, with neon, helium, ozone and hydrogen in tiny amounts.
3. Water vapour (0 to 4% by volume) decreases from the equator to the poles; dust particles act as hygroscopic nuclei for condensation.
Structure (five layers):
4. Troposphere: about 18 km at the equator and 8 km at the poles; contains most of the water vapour, dust and weather; temperature falls about 1°C per 165 m; its upper limit is the tropopause.
5. Stratosphere: up to about 50 km; contains the ozone layer that absorbs ultraviolet rays; temperature rises with height.
6. Mesosphere: up to about 80 km; temperature falls to −100°C; meteors burn here.
7. Thermosphere: 80 to 400 km; has the ionosphere, which reflects radio waves, and temperature rises with height.
8. Exosphere: the uppermost layer, merging into space; very thin air of hydrogen and helium.

Teacher's Note:
1. Cover both composition (gases) and structure (layers) as the question asks for both.
2. Give the approximate height and one key feature for each layer.

Answer: Physiographic divisions of India: (1) The Northern and North-eastern Mountains, (2) The Northern Plain, (3) The Peninsular Plateau, (4) The Indian Desert, (5) The Coastal Plains, (6) The Islands.
The Peninsular Plateau:
1. It is a tableland made of old crystalline, igneous and metamorphic rocks, a part of the Gondwana land, and is the oldest and most stable block.
2. It has two broad divisions: the Central Highlands (north of the Narmada, including the Malwa plateau, Bundelkhand, Baghelkhand and Chotanagpur plateau) and the Deccan Plateau (south of the Narmada).
3. The Deccan Plateau is bordered by the Western Ghats (Sahyadri), which are continuous and high with peaks such as Anai Mudi, and the Eastern Ghats, which are discontinuous and lower.
4. The north-western part of the Deccan has black soil from lava (Deccan Trap), and the north-eastern extension includes the Meghalaya, Karbi Anglong and North Cachar Hills plateau.
5. The Aravalli range on the western side is a very old, highly eroded range; rivers such as the Narmada and the Tapi flow westward through rift valleys.

Teacher's Note:
1. Begin by listing all six divisions and then focus on the peninsular plateau.
2. Contrast the Western Ghats with the Eastern Ghats to show you know the details.

Answer: The monsoon is a seasonal reversal of winds. Its mechanism has these parts:
1. Differential heating: in summer, land heats faster than sea, forming a low pressure over northwest India while the Indian Ocean is cooler and has high pressure.
2. Shift of the ITCZ: the Inter-Tropical Convergence Zone, a low-pressure belt, shifts north to about 20°N–25°N over the Ganga plain; the south-east trades cross the equator and turn right as the south-west monsoon.
3. Tibetan plateau heating: intense heating of Tibet creates strong upward air currents and a low-pressure area high up.
4. Upper air circulation: in summer the westerly jet stream withdraws north of the Himalayas and the tropical easterly jet stream develops over the peninsula; this helps the monsoon burst.
5. Ocean-atmosphere links: the Southern Oscillation (El Nino) affects the strength of monsoon rainfall.
6. Retreat in winter: the ITCZ shifts south, the westerly jet returns and the northeast monsoon blows from land to sea.

Teacher's Note:
1. Link the surface low pressure with the upper air jet streams, which the question stresses.
2. Mention the ITCZ, Tibetan plateau and jet streams to score full marks.

Answer: 1. Earthquake waves are recorded by seismographs; the places where seismic waves are not recorded form the shadow zones.
2. S-waves: they cannot travel through liquids. Seismographs located more than 105° from the epicentre do not record S-waves, so the entire region beyond 105° is the S-wave shadow zone, which shows that the outer core is liquid.
3. P-waves: they pass through solids and liquids but are refracted at the core boundary. They are recorded up to 105°, and not between 105° and 145° (the P-wave shadow zone, a ring-shaped zone around the earth).
4. Beyond 145° the P-waves are recorded again, after passing through the core.
5. Thus the S-wave shadow zone is larger than the P-wave shadow zone, and the shadow zones help us to know the interior of the earth, including that the outer core is liquid.

Teacher's Note:
1. State the angles clearly: 105° and 145°.
2. Explain why S-waves are stopped by the liquid outer core, since that is the main reasoning.