DELHI PUBLIC SCHOOL, FARIDABAD

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1 Class - VII Geography Assignment Unit-ll Q. 1 Multiple choice questions : SECTION A a.all weather phenomena takes place in i. Mesosphere iii. Troposphere ii.exosphere iv.stratosphere b.a Wind Vane is used to see i. Wind Direction iii. Wind Pressure ii.wind Speed iv.air Pollution c.as we go up the atmosphere, temperature i. Increases iii. remains the same ii.decreases iv.first decreases then increases d. The layer which transmits radio waves back to the earth is i. Stratosphere ii. Exosphere iii. Thermosphere iv. Mesosphere e. The monsoon winds are i. Variable iii. Local ii. Seasonal iv. Permanent Q.2 Fill in the blanks :- a. A wind is named according to the from which it blows. b.an instrument which is used to measure the atmospheric pressure is called. c.the horizontal movement of the air along the surface of the earth is known as. d. extends to a height of 50 km above the Troposphere. e. The main source of heat received by the earth is called Q.3 State whether true or false. a.global warming is caused due to the increase in the level of nitrogen gas. b.air pressure is measured by anemometer. c.carbon dioxide is the most abundant gas in the atmosphere. d.plants do not need oxygen gas. e.the seasonal winds blow in a particular direction constantly throughout the year. 74

2 Q. 4 Name the following. a.horizontal motion of air along the surface of the earth. b.the force exerted by atmosphere on the surface of the earth due to its weight. c.winds originating and blowing from the sub-tropical high pressure belts towards the equa torial low pressure belts. d.the winds that blows in particular region due to specific presssure conditions. e.harmful rays from the sun which is prevented by the atmosphere. Q. 5 Short answer type questions :- SECTION B a.what is atmosphere? b.why is temperature in the cities much higher than that of villages? c.why do Astronauts wear special space suits filled with air when they go to the moon? d.how does the atmosphere help in radio communication? e.what is the importance of the troposphere? f.differentiate between weather and climate. Q. 6 Long answer type questions :- a.describe the structure of the atmosphere. Draw a diagram also. b.what is atmospheric pressure? How can we measure it? c.describe Orographic rainfall. Support your answer with appropriate diagram. d.what are the different types of winds? Describe each. e.explain the convectional rainfall and also give a diagram. f.what is the importance of the atmosphere for us? g.what is global warming? How is it caused? What can we do to reduce it? h.how have gases in the air helped life on earth? Q.7 Think and Discuss. a.there remains a low pressure belt all round the year near the equator. b.the poles have a permanent high pressure belt all through the year. c.the amount of insolation decreases from equator towards the poles. 75

3 Class - VII Geography Assignment Unit-ll Ch. : Water Q.1 Multiple choice questions. SECTION A a.the salts and other minerals dissolved in the seas or oceans make its water i. Sweetii. Dead iii. Pollutediv. Saline b.the largest ocean of the world is i. Atlanticii. Indian iii. Pacificiv. Arctic c.the main cause of ocean currents is i. Gravitation iii. Winds IV. Rotation of earth Salty water d.alternate rise and fall of the water in the sea or oceans twice daily is called i. Tideii. Wave iii. Currentsiv. Tsunami e.the Japanese word which means the 'harbour waves' is called : i. Ocean currentsii. Tides iii. Tsunamiiv. Waves Q.2 Fill in the blanks :- a. b. c. d. e. Heat of the sun helps to change water into Huge tidal waves cause Periodic rise and fall of water is termed as High tides are also calledtides., ocean currents move from higher latitudes towards the poles. Q. 3 Match column 'A' with column 'B' :- Column 'A' i.wavesa. ii.tidesb. iii.warm currentsc. iv.cold currentsd. v.tsunamie. vi.ideal fishing ground f. Column 'B' develops at the meeting point of the warm and cold currents means the 'harbour waves' Flow from the polar regions and reduce the temperature of coastal areas are caused by the pushing action of winds are primarily caused by the pull of the moon and the sun Flow from the equatorial region and raise the temperature of coastal areas. 76

4 Q. 4 Short answer type questions :- a.what is water cycle? b.what are tides and how are they caused? c.what are ocean currents? d.what causes waves? e.how are tide useful to us? SECTION B Q. 5 Long answer type questions :- a.what are the different types of tides and how are they caused? Draw diagram. b.what factors are responsible for giving rise to ocean currents? c How are the ocean current beneficial to us? d. Suggest measure to conserve water. When do we celebrate 'World Water Day'? e What are the various factors for the movement of ocean water? Q. 6 Differentiate between the following :- a.warm Ocean Currents of Cold Ocean Currents b.waves and Tides c.ocean currents and waves Q. 7 Think and discuss :- a.the ocean or sea water is saline in taste. b.the hot deserts world over are found along the cold currents. c.the warm oceanic currents are helpful in navigation. 77

5 Class-VII Geography Worksheet Unit-ll Q 1. On an outline map of the world locate the following. Note : Mark Warm Ocean Current with Red, Cold Ocean Current with Blue. a.gulf stream current b.labrador current c.kuroshio current d.oyashio current e.brazilian current f.north Atlantic current g.california current h. West Australian current 78

6 Class - VII Geography Worksheet Unit-ll TYPES OF RAIN FALL 1. OROGRAPHIC RAIN FALL i. The moist air mass is forced to ascend (rise along the slope of the mountain or hill) ii. As an air mass rises upward, cooling take place followed by condensation and precipitation in the form of rainfall. iii. The word Orographic is taken from the Greek word 'oros' which means mountain, iv. Sometimes a hill or a mountain comes in the path of moisture laden winds, v. It is also called 'relief rainfall'. vi. Wind ward side of the mountain gets more rainfall than the Leeward side. For eg. Mahabaleshwar on the windward side of the Western Ghats receives more rainfall than Pune on the Leeward side. wind* wtmt **nup cacn.1** rittmtnm n- sst OROGRAPHIC RAINFALL 2. CONVECTIONAL RAINFALL i. When an air mass comes in contact with the hot surface of the earth, it gets heated, expands, becomes light and thus rises up in the form of vertical air currents. ii. After reaching the upper layers of the atmosphere the hot air looses heat as it cools at higher altitude. iii. This leads to condensation of moisture contained in the air and formation of clouds. Cmi^iUa.ni avy air descending ist air rising CONVENCTIONAL RAINFALL 79

7 iv. The cool air from higher altitude comes down to occupy the space created by rising air. v. This type of rainfall is a common feature in equatorial regions because these regions receive direct sunlight and thus high temperature. 3. FRONTAL RAIN FALL i. The place of meeting of a warm and a cold air mass is called a 'front'. ii. When a warm air mass and a cold air mass meet, the warm air mass being lighter climbs over the cold air mass along the front. iii. The rising warm air mass cools down and condensation of water vapour takes place, iv. This type of rainfall is common in mid - latitude regions [231/2 to 661/2 - temperate zone] v. It is also called cyclonic rainfall. FRONTAL RAIN 80