Question 1

Question 1(b)(i) What is meant by the inclination of the Earth's axis?(ii) At what angle is the Earth's axis inclined?

Accepted Answer

(i) The axis on which earth rotates makes an angle of 66 1⁄2° with the plane of ecliptic and is tilted 23 1⁄2° from a line perpendicular to that plane. This tilt of earth is called inclination of the Earth's axis.(ii) The Earth's axis is inclined at 23 1⁄2°.

Question 2

Question 1(g)(i) Name any two sources of soil pollution.(ii) State the impact of soil pollution on agricultural production.

Accepted Answer

(i) Sources of soil pollution are:Industrial waste — Industrial waste containing chemicals, when dumped in soil, causes soil pollution. For example, fly ash from thermal plants, chemicals from oil refineries pollute the soil.Urban commercial and domestic waste — Non-biodegradable wastes like glass, plastic, polythene bags etc, either remain in the soil and take a long time to decompose.(ii) Chemical fertilizers destroy the soil's natural balance. It makes the soil vulnerable to erosion, leaves it lacking in nutrients and starts a vicious cycle in which more fertilizers must be used to make up for nutrient depletion in soil. Also, the toxic chemicals may enter the food chain and lead to biomagnification.

Question 3

Question 1(i)How does the rotation of the earth influence the direction of the ocean currents?

Accepted Answer

The Earth rotates on its axis from west to east. This rotation is the cause of a deflective force known as Coriolis Force which deflects the general direction of the ocean currents. For example, the currents flowing from Equator towards the North and South Poles are deflected to their right in the Northern Hemisphere and towards their left in the Southern Hemisphere.

Question 4

Question 1(j)(i) What is Coriolis Effect?(ii) How does it affect the planetary winds?

Accepted Answer

(i) A deflective force that, as a result of the earth's rotation, deflects moving objects to the right in the northern hemisphere and in the left in the southern hemisphere is called coriolis force. This deflective effect of coriolis force is called coriolis effect. It affects the movement of ocean currents and winds.(ii) The planetary winds do not blow straight from the low pressure belt to high pressure belt but their direction is affected by coriolis force. For example, trade winds in Southern Hemisphere do not blow from south to north but they blow from south-east to north-west.

Question 5

Question 3(a)(i) Why are latitudes also called parallels of latitude?(ii) Why are all the lines of longitude of the same length?

Accepted Answer

(i) Latitudes are known as parallels of latitude as each of them is an imaginary circle parallel to the Equator and centered on the polar axis.(ii) All longitudes join the two poles. Therefore, they are of same length.

Question 6

Question 3(c)Give a geographical reason for each of the following:Great circles are the shortest routes between two places.The Earth is a habitable planet.Kuala Lumpur rotates faster on the Earth's axis than London.

Accepted Answer

The shortest routes between two places is not the parallel latitudes but the arc of Great Circle as the arc is shortest distance between two points on the circle.The Earth is a habitable planet because it has water and atmosphere(oxygen). The atmosphere keeps the earth warm and maintains the temperature of the earth.Kuala Lumpur is situated near the Equator and London is situated on higher latitudes. The speed of rotation at Kuala Lumpur is much faster than that at London because as the latitude increases the speed of rotation decreases.

Question 7

Question 3(d)Draw a neat labelled diagram showing the position of the Earth during solstice.

Accepted Answer

Below diagram shows Summer Solstice in the Northern Hemisphere:

Question 8

Question 4(a)What is the composition of the Earth's crust?

Accepted Answer

The earth's crust consists of two layers - SIAL and SIMA.The material of the upper or continental part of the earth's crust, characterized by relatively low density is called the SIAL layer.The SIAL layer has predominance of Silica and Aluminium. It is also known as granite layer which floats on SIMA.The lower layer of the earth's outer crust that underlies the SIAL is SIMA layer. It consists of Silica and Magnesium and it is also known as basaltic layer.

Question 9

Question 4(b)(i) Differentiate between intermontane plateau and volcanic plateau.(ii) Give an example of residual mountain and an example of depositional plain

Accepted Answer

(i) Difference between intermontane plateau and volcanic plateau:Intermontane plateauVolcanic plateauThese are surrounded by hills and mountains on all the sides. They are formed along with fold mountains.They are formed by numerous volcanic eruptions that slowly build up over time.For example - the Tibetan plateauFor example - the Peninsular plateau of India(ii) Sierra in Spain is an example of residual mountain and Northern plains of India is an example of depositional plain.

Question 10

Question 4(d)Give a reason for each of the following:Igneous rocks are also called Primary rocksFossils are present in Sedimentary rocksThe core of the Earth is in a semi—solid state

Accepted Answer

Igneous rocks are also called primary rocks because they are formed when molten lava solidifies. Sedimentary rocks and metamorphic rocks are formed from other rocks.Sedimentary rocks which are organically formed consist of remains or forms of sea plants and animals which have been buried and preserved in these rocks for a long time. They may have fossils trapped in their layers while formation of sedimentary rocks.The core of the Earth is in a semi—solid state because of extreme pressure which is 3 million tonnes greater at core than at the surface.

Question 11

Question 5(c)Give a geographical reason for each of the following:Volcanic activity and earthquakes occur in the same belt.All rivers do not form a delta.Chemical weathering is more common in the tropical regions.

Accepted Answer

The volcanoes and earthquakes are associated with each other. Both occur along the faults between the tectonic plates. Therefore, belt of their occurrence is same.When a river flows through a rocky area, and carries very little load because of the steep terrain, it forms a narrow opening at its mouth which gradually widens out into the sea. Such rivers do not form delta.Chemical weathering is more common in the tropical regions because the climate of tropical region is hot and humid. High temperature and presence of moisture increases the rate of reaction thereby increasing the rate of chemical weathering.

Question 12

Question 5(d)Explain the meaning of the following terms:Deflation hollowRiver meanderBlock disintegration.

Accepted Answer

Deflation hollow — The wind lowers the ground by blowing away the unconsolidated materials giving rise to large depressions called deflation hollow.River meander — S-shaped loops formed in the middle course of the river in plains are called meanders. When the river moves slowly, it bends on a flat surface and swings outward to form larger meanders.Block disintegration — It is a type of weathering in which rocks split along the joints into large rectangular shaped blocks. It occurs in well-jointed rock such as granite due to temperature change. It is partially effective in areas with great diurnal range of temperature (10°C to 15°C or more) and barren rocks without a protective vegetation cover.

Question 13

Question 6(a)State four factors that affect the movement of ocean currents.

Accepted Answer

Four factors that affect the movement of ocean current are:Variation in Sea Water TemperatureVariation in Sea water SalinityConfiguration of CoastlinePlanetary winds

Question 14

Question 6(b)Draw a neat and well labelled diagram showing the two types of tides.

Accepted Answer

Spring TideNeap Tide

Question 15

Question 6(c)Give a reason for each of the following:Newfoundland has rich fishing grounds.The eastern coast of Japan is warm even in January.The tidal range differs from one water body to the other.

Accepted Answer

Newfoundland, where Gulf stream (warm) and Labrador (cold) currents meet has rich fishing ground, because the mixing of the cold and warm currents provides ideal temperature conditions for the life of fish.The eastern coast of Japan is warm even in January because of warm Kuroshio Current. It is the most important warm current of North Pacific Ocean. It's average temperature remains 18°C.The tidal range differs from one water body to the other. In the open oceans such as Atlantic, tides flow and ebb regularly twice a day. The difference in height between high and low tides, may be only a half metre, but in shallow marginal sea, it can increase upto 10 metres. In the enclosed seas or sheltered seas such as Mediterranean or Baltic, the range may be very small.

Question 16

Question 6(d)State three ways in which oceans are important to us.

Accepted Answer

Three ways in which oceans are important to us are:They regulate our climate.They provide most of the oxygen.They provide food in the form of fish and other sea foods.

Question 17

Question 7(a)"Higher the latitude, lower is the temperature."Justify the statement with an example.

Accepted Answer

At higher latitude, the sun rays have to cover more distance to reach the earth's surface due to spherical shape of earth. Thus, they lose more heat as compared to the lower latitudes which receive direct rays of the sun. For example, the area around equator (0°) is hot and humid while the areas near arctic circle (66 1/2°) is cold throughout the year.

Question 18

Question 7(b)(i) What is the cause of ozone depletion?(ii) State the impact of ozone depletion on human life.

Accepted Answer

(i) The causes of destruction of ozone layer are:Emission of Nitrogen Oxide by a large number of supersonic transport aeroplanes causes deterioration of ozone layer.Release of synthetic chemicals primarily Chlorofluoro-carbons(CFCs) into the atmosphere is the most important cause of depletion of ozone layer.(ii) Following are the impacts of ozone depletion on human life:It will allow excessive radiation of ultraviolet rays which can render man and animal blind.It can cause crop damage,It can burn skin and cause cancer.

Question 19

Question 7(c)Give a reason for each of the following:The snow on the slope of Himalayas in Nepal melt faster than that on the slope towards Tibet.Tropical deserts have a large annual range of temperatures.Equatorial regions have low atmospheric pressure throughout the year.

Accepted Answer

The Himalayan area near Tibet are situated on higher latitudes as compared to the Himalayas of Nepal. The temperature decreases with increase in latitudes. Therefore, the snow on the slope of Himalayas in Nepal melts faster than that on the slope towards Tibet.Tropical deserts are free of cloud cover. This results in their quick heating as well as quick cooling due to radiation of heat. Therefore, tropical deserts have a large annual range of temperatures.Equatorial region receives maximum insolation and heat throughout the year. The hot air rises up creating low pressure in this area.

Question 20

Question 7(d)Draw a neat labelled diagram of the structure of the Earth's atmosphere.

Accepted Answer

Below diagram illustrates the structure of the atmosphere:

Specimen Paper

Part I

Part Ii