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Class 8 Geography Chapter 3 Atmosphere, , I. Fill In The Blanks., Question 1., The two major gases of the atmosphere are _____, Answer:, Nitrogen and oxygen, Question 2., The lowest layer of the atmosphere is _____, Answer:, Troposphere, Question 3., The average cur pressure of the atmosphere at the sea level is _____, Answer:, 1013.25 mb, Question 4., Westerlies is also known as _____, Answer:, Anti trade winds, Atmosphere 8th Standard Notes Question 5., The scientific study of weather is _____, Answer:, Meteorology, II. Answer The Following Questions:, Question 1., What is atmosphere?, Answer:, The thin blanket of air that surrounds the earth is called the Atmosphere. This layer of gases
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forms a protective boundary between the outer space and the earth’s space. It is the second, layer of the earth., Question 2., Name the important layers of the atmosphere., Answer:, The atmosphere may be divided into five important layers. They are Troposphere,, Stratosphere, Mesosphere, Thermosphere, and Exosphere., Question 3., What is the significance of the ozone layer?, Answer:, The ozone layer is the most important gas which absorbs ‘ultraviolet rays’ of the sun and, protects all forms of life on the earth. This layer is free from clouds and other important, weather phenomena and provides ideal flying conditions for jet aircraft., Question 4., What is Doldrum? Where is it found?, Answer:, The Equatorial low-pressure belt is a zone of high temperature and low pressure. It lies, between 0° to 5° North and South of the equator. This region gets direct rays of the Sun, almost throughout the year. Hence air is always very warm and hot. This is a calm region with, very little wind so it is called “Doldrum” means ‘belt of clam’. This region is also called the, Inter-Tropical convergence zone where the trade Winds coverage., Question 5., Name the different types of planetary winds., Answer:, Planetary winds are also called permanent or prevailing or regular winds that blow more or, less in the same direction throughout the year. Trade winds, westerlies, or Anti-trade winds,, and the polar winds are the three types of planetary winds., Question 6., What are the local winds? Give any two examples., Answer:, Periodic winds are the result of variation in local temperature, pressure, humidity which in, turn are attributed to the formation of air currents, crossing mountain ranges, valleys and, other relief barriers., Eg:- Mountain breeze, Sea breeze, Valley breeze., Question 7., Mention the different types of clouds., Answer:, Cloud is a mass of small water drops or ice crystal, formed by the condensation of the water
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in the atmosphere usually at a considerable height above the earth’s surface. The important, types of clouds are Stratus, Cumulus, Cirrus, Nimbus, etc., Question 8., Distinguish between weather and climate., Answer:, Weather: The atmospheric conditions of a smaller area at a particular time is called weather., The scientific study of weather is called ‘Meteorology’. Climate: Climate is the average, condition of the atmosphere over a long period of time of a larger area. The scientific study of, climate is called ‘Climatology’., III. Define The Following:, 1. Ionosphere :, It is also called Troposphere. It is the lowest layer of the atmosphere. It extends upto 18 kms at, the equator and 8 Kms near the poles. All-weather changes occur in the troposphere., 2. Normal lapse rate :, It is the decreasing rate of temperature with the increase of altitude. The rate of decrease is 1°C, for every 165 meters of 6.4° for every 1000 meters of height., 3. Torrid zone :, This is the zone of high temperature. This region is found between 0° or equator and Tropic of, Cancer in the north and the Equator and Tropic of Capricorn in the south., 4.Horse latitudes :, North subtropical high-pressure belt is found between 30° to 35° north latitudes popularly, called ‘horse latitude’., 5.Orographic rainfall :, It is also called ‘Mountain rainfall’ or ‘Relief rainfall’. When moisture-laden air is obstructed by a, mountain barrier, the air is forced to rise up. As the air rises upwards, it cools and gets, saturated. Further cooling or this air causes condensation resulting in orographic or mountain, rainfall., 6. Climatology :, The scientific study of climate is called Climatology., Class 8 Social Science Atmosphere Additional Questions and Answers, I. Multiple Choice Questions:, 1. The lowest layer of the atmosphere is ______, (a) Troposphere, (b) Stratosphere, (c) Mesosphere, (d) Exosphere.
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Answer:, (a) Troposphere, 2. The layer which lies next to mesosphere is ______, (a) Exosphere, (b) Thermosphere, (c) Stratosphere, (d) Mesosphere., Answer:, (b) Thermosphere, 3. An atmospheric condition of a place at a given time is called ______, (a) Season, (b) Climate, (c) Weather, (d) Temperature., Answer:, (c) Weather, 4. The average weather condition of an area over a long period of time is called ______, (a) Temperature, (b) Weather, (c) Season, (d) Climate, Answer:, (d) Climate, 5. Incoming solar radiation from the sun to the earth is called ______, (a) Insolation, (b) Isolation, (c) Isotherm, (d) Inflonation, Answer:, (a) Insolation, 6. The instrument used to measure temperature is ______, (a) Barometer, (b) Thermometer, (c) Exometer, (d) Hydrometer, Answer:, (b) Thermometer
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7. Air pressure is measured by an instrument called ______, (a) Hydrometer, (b) Exometer, (c) Barometer, (d) Thermometer., Answer:, (c) Barometer, 8. The unit used to show the pressure is ______, (a) Megabar, (b) Multibar, (b) Minibar, (d) Millibar., Answer:, (d) Millibar., 9. ‘Doldrum’ means ______, (a) Calm, (b) Bell of calm, (c) Calm, (d)Salm, Answer:, (b) Bell of calm, 10. The instrument used to measure the speed of the wind is ______, (a) Barometer, (b) Ammeter, (c) Anemometer, (d) Hexometer., Answer:, (c) Anemometer, II. Fill In The Blanks, Question 1., ______ is the third layer in the earth’s atmosphere., Answer:, Mesosphere., Question 2., ______ and ______ are the important thermometers used to measure atmospheric, temperature., Answer:, Centigrade and Fahrenhei
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Question 3., ______ is the most important factor that influences atmospheric pressure., Answer:, Temperature, Question 4., ______ is the horizontal movement of the air on the surface of the earth., Answer:, Wind, Question 5., The direction of the wind is shown by an instrument called ______, Answer:, Wind vane or weather clock., Question 6., ______ are also called periodic winds., Answer:, Seasonal winds, Question 7., Cumulus clouds are popularly called ______, Answer:, Wool packs., Question 8., Cirrus clouds popular name is ______, Answer:, Mare’s tail or witch’s broom, III. Answer The Following Questions:, Question 1., What are the components of the atmosphere?, Answer:, The important components of the atmosphere are Nitrogen, oxygen, Argon, carbon dioxide,, ozone., Question 2., What are the important factors that influence atmospheric temperature?, Answer:, The important factors that influence atmospheric temperature are latitude, altitude, distance, from the sea, wind, ocean currents, relief, clouds, rainfall. Etc.
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Question 3., What is Torrid zone?, Answer:, This is the zone of high temperature. This region is found between 0° or equator and Tropic of, cancer in the north and the equator and Tropic of Capricorn in the south., Question 4., What is temperate zone?, Answer:, This is the region where the temperature is neither very hot nor cold. This region lies between, 23½°N to 66½°N and 23½°S to 66½°S., Question 5., What are Isotherms?, Answer:, Isotherms are lines drown on the map or globe connecting places having the same, temperature., Question 6., What are Isobars?, Answer:, These are Imaginary lines drawn on the map or globe connecting places having the same, pressure., Question 7., What is atmospheric pressure?, Answer:, Air has weight and it exerts pressure. This is called atmospheric pressure., Question 8., Name the major pressure belts of the earth., Answer:, Major pressure belts of the earth are:, 1., 2., 3., 4., 5., 6., 7., , The equatorial low-pressure belt., North sub-tropical high-pressure belt., South sub-tropical high-pressure belt., North subpolar low-pressure belt., South subpolar low-pressure belt., North polar high-pressure belt., South polar high-pressure belt., , Question 9., What is the cloud?
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Answer:, Clouds are a mass of small water drops or ice crystals, formed by the condensation of the water, in the atmosphere, usually at a considerable height above the earth’s surface., Question 10., Name the types of Rainfall., Answer:, The important types of Rainfall are:, 8. Convectional rainfall, 9. Orographic rainfall and, 10. Cyclonic rainfall., IV Terms to Remember, 1. Insolation: It means incoming solar radiation from the sun to the earth., 2. Inversion of temperature: In some situations, temperature also increases with increasing, height. This takes place is mountain valleys during long winter nights with a clear sky, dry air, no, wind, and snow-covered surface., 3. Anemometer: Used to measure the speed of the wind., 4. Roaring forties: The westerlies of the southern hemisphere are very strong over the oceans, around 50° south latitudes., 5. Nimbus: Nimbus clouds are rain clouds that occur at low levels. These clouds have the shape, of stratus or cumulus. They are dark grey or black in appearance. They cause heavy rainfall or, snowfall., 6. Meteorology: The scientific study of weather is Meteorology.
