{"id":118761,"date":"2022-04-28T14:49:47","date_gmt":"2022-04-28T09:19:47","guid":{"rendered":"https:\/\/www.mapsofindia.com\/my-india\/?p=118761"},"modified":"2022-04-28T14:49:47","modified_gmt":"2022-04-28T09:19:47","slug":"chapter-8-composition-and-structure-of-atmosphere-questions-and-answers-ncert-solutions-for-class-11-geographyfundamentals-of-physical-geography","status":"publish","type":"post","link":"https:\/\/www.mapsofindia.com\/my-india\/education\/chapter-8-composition-and-structure-of-atmosphere-questions-and-answers-ncert-solutions-for-class-11-geographyfundamentals-of-physical-geography","title":{"rendered":"Chapter 8 – Composition and Structure of Atmosphere Questions and Answers: NCERT Solutions for Class 11 Geography(Fundamentals of Physical Geography)"},"content":{"rendered":"

1. Multiple choice questions.<\/h3>\n

Question 1(i).
\nWhich one of the following gases constitutes the major portion of the atmosphere?
\n(a) Oxygen
\n(b) Nitrogen
\n(c) Argon
\n(d) Carbon dioxide.<\/h2>\n

Answer:
\n(b) Nitrogen<\/h3>\n

Question 1(ii).
\nAtmospheric layer important for human beings is:
\n(a) Stratosphere
\n(b) Mesosphere
\n(c) Troposphere
\n(d) Ionosphere.<\/h2>\n

Answer:
\n(c) Troposphere<\/h3>\n

Question 1(iii).
\nSea salt, pollen, ash, smoke soot, fine soil hese are associated with:
\n(a) Gases
\n(b) Dust particles
\n(c) Water vapour
\n(d) Meteors.<\/h2>\n

Answer:
\n(b) Dust particles<\/h3>\n

Question 1(iv).
\nOxygen gas is in negligible quantity at the height of atmosphere:
\n(a) 90 km
\n(b) 120 km
\n(c) 100 km
\n(d) 150 km.<\/h2>\n

Answer:
\n(b) 120 km<\/h3>\n

Question 1(v).
\nWhich one of the following gases is transparent to incoming solar radiation and opaque to outgoing terrestrial radiation?
\n(a) Oxygen
\n(b) Nitrogen
\n(c) Helium
\n(d) Carbon dioxide.<\/h2>\n

Answer:
\n(d) Carbon dioxide.<\/h3>\n

2. Answer the following questions in about 30 words.
\nQuestion 2(i).
\nWhat do you understand by atmosphere?<\/h2>\n

Answer:
\nThe atmosphere is composed of gases, water vapour and dust particles. The proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.<\/h3>\n

Question 2(ii).
\nWhat are the elements of weather and climate?<\/h2>\n

Answer:
\nWeather is conditions of temperature, humidity, pressure, etc at a given point of time while climate is condition of these elements for a longer period of time. Following are the important elements of weather and climate:
\nTemperature: It affects weather as well as climate.
\nPressure: Pressure keeps on decreasing with increase in height.
\nWind: The flow of wind also affects weather and climate.
\nHumidity: Clouds and rain are important factors of climate.<\/h3>\n

Question 2(iii).
\nDescribe the composition of atmosphere.<\/h2>\n

Answer:
\nThe atmosphere is composed of gases, water vapour and dust particles. Nitrogen constitutes 78.8%, oxygen contributes 20.94% and argon contributes 0.93% in atmosphere. Other gases include carbon dioxide, helium, ozone, methane, hydrogen, krypton, xenon and neon, etc. Nitrogen and oxygen together constitute 99% of the atmosphere. Neon, krypton, xenon are scarce gases. The proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.<\/h3>\n

Question 2(iv).
\nWhy is troposphere the most important of all the layers of the atmosphere?<\/h2>\n

Answer:
\nThe troposphere is the lowermost layer of the atmosphere. Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator. It is most important layer of the atmosphere because:
\nThickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents.
\nThis layer contains dust particles and water vapour.
\nAll changes in climate and weather take place in this layer.
\nThe temperature in this layer decreases at the rate of 1\u00b0C for every 165m of height.
\nAll biological activities take place in this layer.<\/h3>\n

3. Answer the following questions in about 150 words.
\nQuestion 3(i).
\nDescribe the composition of the atmosphere.<\/h2>\n

Answer:
\nThe composition of the atmosphere can be understood by considering following table.
\nGases of the Atmosphere
\nConstituent
\nFormulae
\n% by Volume
\nNitrogen
\nN2
\n78.08
\nOxygen
\nO.
\n20.95
\nArgon
\nAr
\n0.93
\nCarbon dioxide
\nCO2
\n0.036
\nNeon
\nNe
\n0.002
\nHelium
\nHe
\n0.0005
\nKrypton
\nKr
\n0.001
\nXenon
\nXe
\n0.00009
\nHydrogen
\nH2
\n0.00005
\nThe atmosphere is composed of gases, water vapour and dust particles. Nitrogen constitutes 78.8%, oxygen contributes 20.94% and argon contributes 0.93% in atmosphere. Other gases include carbon dioxide, helium, ozone, methane, hydrogen, krypton, xenon and neon, etc. Nitrogen and oxygen together constitute 99% of the atmosphere. Neon, krypton, xenon are scarce gases. The proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.
\nCarbon dioxide is meteorologically a very important gas as it is transparent to the incoming solar radiation but opaque to the outgoing terrestrial radiation. It absorbs a part of terrestrial radiation and reflects back some part of it towards the earth\u2019s surface. It is largely responsible for the green house effect. Ozone is another important component of the atmosphere. It is found between 10 and 50 km above the earth\u2019s surface and acts as a filter. It absorbs the ultra-violet rays radiating from the sun. It prevents them from reaching the surface of the earth.
\nWater vapour is such a variable gas in the atmosphere, which decreases with altitude. In the warm and wet tropics, it may account for four per cent of the air by volume, while in the dry and cold areas of desert and polar regions, it may be less than one per cent of the air. Atmosphere has a sufficient capacity to keep small solid particles, which may originate from, different sources and include sea salts, fine soil, smoke-soot, ash, pollen, dust and disintegrated particles of meteors.<\/h3>\n

Question 3(ii).
\nDraw a suitable diagram for the structure of the atmosphere and label it and describe it.<\/h2>\n

Answer:
\nThe atmosphere consists of different layers with varying density and temperature. Density is highest near the surface of the earth and decreases with increasing altitude. The atmosphere is divided into five different layers depending upon the temperature condition.
\nThey are: troposphere, stratosphere, mesosphere, thermosphere and exosphere.<\/h3>\n

\"\"<\/p>\n

1. Troposphere: The troposphere is the lowermost layer of the atmosphere. Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator. Thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. This layer contains dust particles and water vapour. All changes in climate and weather take place in this layer. The temperature in this layer decreases at the rate of 1\u00b0C for every 165m of height.
\n2. Stratosphere: The stratosphere is found above the tropopause and extends up to a height of 50 km. One important feature of the stratosphere is that it contains the ozone layer. This layer absorbs ultra-violet radiation and shields life on the earth from intense, harmful form of energy.
\n3. Mesosphere: The mesosphere lies above the stratosphere, which extends up to a height of 80 km. In this layer, temperature starts decreasing with the increase in altitude and reaches up to minus 100\u00b0C at the height of 80 km.
\n4. Ionosphere; The ionosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions, and hence, it is known as ionosphere. Radio waves transmitted from the earth are reflected back to the earth by this layer.
\nTemperature here starts increasing with height.
\n5. Exosphere: The uppermost layer of the atmosphere above the thermosphere is known as the exosphere. This is the highest layer but very little is known about it.<\/h3>\n

Multiple Choice Questions<\/h3>\n

Question 1.
\nWhich of the following is an important component of atmosphere?
\n(a) Water vapours
\n(b) Dust particles
\n(c) Gases
\n(d) All of the above.<\/h2>\n

Answer:
\n(d) All of the above<\/h3>\n

Question 2.
\nWhat is the upper layer of mesosphere called?
\n(a) Mesosphere
\n(b) Ionosphere
\n(c) Troposphere
\n(d) Stratosphere.<\/h2>\n

Answer:
\n(a) Mesosphere<\/h3>\n

Question 3.
\nWhich layer of atmosphere has electronically charged particles?
\n(a) Mesosphere
\n(b) Ionosphere
\n(c) Troposphere
\n(d) Stratosphere.<\/h2>\n

Answer:
\n(b) Ionosphere<\/h3>\n

Question 4.
\nWhich of the following is the uppermost layer of the atmosphere?
\n(a) Exosphere
\n(b) Ionosphere
\n(c) Troposphere
\n(d) Stratosphere.<\/h2>\n

Answer:
\n(a) Exosphere<\/h3>\n

Question 5.
\nWhich of the following is the lowest layer of the earth?
\n(a) Mesosphere
\n(b) Ionosphere
\n(c) Troposphere
\n(d) Stratosphere.<\/h2>\n

Answer:
\n(c) Troposphere<\/h3>\n

Question 6.
\nThe air is an integral part of the earth\u2019s mass and 99 per cent of the total mass of the atmosphere is confined to the height of how many km from the earth\u2019s surface?
\n(a) 10 km
\n(b) 12 km
\n(c) 24 km
\n(d) 32 km.<\/h2>\n

Answer:
\n(d) 32 km<\/h3>\n

Question 7.
\nTo what height carbon dioxide and water vapours are found in atmosphere?
\n(a) 60 km
\n(b) 75 km
\n(c) 90 km
\n(d) 100 km.<\/h2>\n

Answer:
\n(c) 90 km<\/h3>\n

Question 8.
\nTo what height is ozone found?
\n(a) 10 to 50 km
\n(b) 5 to 60 km
\n(c) 30 to 80 km
\n(d) 40 to 90 km.<\/h2>\n

Answer:
\n(a) 10 to 50 km<\/h3>\n

Question 9.
\nWhich of the following layer of atmosphere is most important for life?
\n(a) Nitrogen
\n(b) Oxygen
\n(c) Ozone
\n(d) Carbon dioxide.<\/h2>\n

Answer:
\n(c) Ozone<\/h3>\n

Question 10.
\nWhat are causes behind increasing density of carbon dioxide?
\n(\u0430) Burning of fossil fuels
\n(b) Killing animals
\n(c) Exploitation of minerals
\n(d) Ozone layer depletion.<\/h2>\n

Answer:
\n(a) Burning of fossil fuels.<\/h3>\n

Very Short Answer Type Questions<\/h3>\n

Question 1.
\nBy which elements is atmosphere made up of?<\/h2>\n

Answer:
\nAtmosphere is made up of gases, water vapours and dust particles.<\/h3>\n

Question 2.
\nWhat percent of earth mass is constituted by air and it is confined to what height?<\/h2>\n

Answer:
\nThe air is an integral part of the earth\u2019s mass and 99 percent of the total mass of the atmosphere is confined to the height of 32 km from the earth\u2019s surface.<\/h3>\n

Question 3.
\nHow does the composition of air keep changing in upper layers of the earth?<\/h2>\n

Answer:
\nThe proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.<\/h3>\n

Question 4.
\nOzone is an important constituent of atmosphere How?<\/h2>\n

Answer:
\nOzone is another important component of the atmosphere. It is found between 10 and 50 km above the earth\u2019s surface and acts as a filter. It absorbs the ultra-violet rays radiating from the sun. It prevents them from reaching the surface of the earth.<\/h3>\n

Question 5.
\nWhat do you mean by tropopause?<\/h2>\n

Answer:
\nThe zone separating the troposphere from stratosphere is known as the tropopause.<\/h3>\n

Question 6.
\nWhat is an important feature of stratosphere?<\/h2>\n

Answer: The stratosphere is found above the tropopause and extends up to a height of 50 km. One important feature of the stratosphere is that it contains the ozone layer. This layer absorbs ultra-violet radiation and shields life on the earth from intense, harmful form of energy.<\/h3>\n

Question 7.
\nWhat is an important feature of troposphere?<\/h2>\n

Answer:
\nThe troposphere is the lowermost layer of the atmosphere. Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator. Thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. This layer contains dust particles and water vapour. All changes in climate and weather take place in this layer. The temperature in this layer decreases at the rate of 1 C for every 165m of height.<\/h3>\n

Question 8.
\nName the gases found in atmosphere.<\/h2>\n

Answer:
\nThe atmosphere is composed of gases, water vapour and dust particles. Nitrogen constitutes 78.8%, oxygen contributes 20.94% and argon contributes 0.93% in atmosphere. Other gases include carbon dioxide, helium, ozone, methane, hydrogen, krypton, xenon and neon, etc.<\/h3>\n

Question 9.
\nExplain important features of ionosphere.<\/h2>\n

Answer:
\nThe ionosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions, and hence, it is known as ionosphere. Radio waves transmitted from the earth are reflected back to the earth by this layer. Temperature here starts increasing with height.<\/h3>\n

Short Answer Type Questions<\/h3>\n

Question 1.
\nWrite a short note on water vapours.<\/h2>\n

Answer:
\nWater vapour:
\nThe amount of water vapour decreases with the altitudes. In warm and wet tropics, it accounts for 4% of the air by volume whereas in dry and cold areas of deserts and polar regions, it may be less then 1% of the air.
\nIt also decreases from the equator towards the poles.
\nIt absorbs parts of the insolation received from the sun and preserves the earth\u2019s radiated heat and thus acts as a blanket by allowing the earth neither to become too hot nor too cold.<\/h3>\n

Question 2.
\nExplain about dust particles.<\/h2>\n

Answer:
\nDust particles:
\nDust particles are concentrated in the lower layers of the atmosphere but sometimes conventional currents take them to the higher height.
\nDust particles includes sea salts, fine soil, smoke, ashes, pollens, dust, disintegrated particles of meteors.
\nDust particles and salt particles act as a hygroscopic nuclei around which water condenses into water vapour to produce clouds.
\nDust particles produce optical phenomenon which makes the sky look beautiful at dawn and dusk.
\nSky looks blue due to the presence of dust particles and water vapour which are scattered in the atmosphere.<\/h3>\n

Long Answer Type Questions<\/h3>\n

Question 1.
\nWrite about elements of weather and climate in detail.<\/h2>\n

Answer:
\nThe main elements of atmosphere which are subject to change and which influence human life on earth are temperature, pressure, winds, humidity, clouds and precipitation. These elements act and react on each other. These elements determine the direction and speed of wind, amount of sunlight received, cloud formation and amount of rainfall. These in turn affect weather and climate. These factors behave differently in different places. All these elements are affected by a number of factors in turn. For example, temperature is affected by latitude and height; humidity is affected by distance from the sun and pressure is affected by height from sea level.<\/h3>\n

Question 2.
\nWrite about the structure of atmosphere in detail.<\/h2>\n

Answer:
\nStructure of Atmosphere: The layers of atmosphere differ from one another with respect to density and temperature. On the basis of chemical composition the atmosphere is mainly divided into
\n1. Homosphere
\n2. Hetrosphere
\n1. Homosphere:
\nIt extends upto 90 km.
\nIt is uniform in chemical composition.
\nIt consists of three layers
\nTroposphere
\nStratosphere
\nMesosphere
\nTroposphere:
\nLower most layer of atmosphere
\nAverage height is 13 km although it is roughly 8 km.
\nThe thickness of troposphere is greater at equation due to upward transportations of heat by conventional currents. This layer consists of dust particles and water vapours.
\nThe temperature decrease with height in this layer at a rate ldegree for every 165 m. this is known as Normal Lapse Rate.
\nIt is layer is important for all biological activities besides that all climatic and weather conditions takes place in this layer.
\nTropopause:
\nThe upper limit of troposphere separating it from stratosphere is called tropopause. It is very unstable at a thin layer and very thin layers of 1.5 km thickness.
\nThe temperature of tropopause is -80degree centigrade censius at equator and -40 degree centigrade at poles.
\nThe jet planes at the other activities occur in this layer.
\nStratosphere:
\nIt extends upto 50km.
\nIt is thicker at poles then at equator.
\nThe temperature is almost constant in its lower portion upto 20 km and their it gradually increases upto 50 km due to the presence of Ozone which absorbs UV rays.
\nThe temperature rises in the upper limits of the stratosphere as there are no clouds, no conventional currents, no dust particles and the air moves in the horizontal direction. The upper\u2019 limit of stratosphere is called stratosphere which has concentration of Ozone gas.
\nMesosphere:
\nIt extends from 50* to 90 km.
\nTemperature decreases with height in this layer and false upto minus 100degree centigrade at a height of 80-90 km. this is due to the clouds in high latitudes.
\nThe upper limit of Mesosphere is called as Mesopause.
\n2. Hetrosphere:
\nIt has heterogeneous chemical.
\nIt consist of two layers
\nIonosphere
\nExosphere
\nIonosphere
\nIt extends from 80 to 400 km above the mesopause.
\nIt contains electrically charged particles known as ions.
\nExosphere
\nIt is the uppermost layer of the atmosphere above the thermosphere.<\/h3>\n","protected":false},"excerpt":{"rendered":"

Class 11 Geography(Fundamentals of Physical Geography) NCERT book solutions for Chapter 8 – Composition and Structure of Atmosphere Questions and Answers.<\/p>\n","protected":false},"author":21830,"featured_media":118724,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":{"0":"post-118761","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-education"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/posts\/118761","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/users\/21830"}],"replies":[{"embeddable":true,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/comments?post=118761"}],"version-history":[{"count":1,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/posts\/118761\/revisions"}],"predecessor-version":[{"id":118764,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/posts\/118761\/revisions\/118764"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/media\/118724"}],"wp:attachment":[{"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/media?parent=118761"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/categories?post=118761"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.mapsofindia.com\/my-india\/wp-json\/wp\/v2\/tags?post=118761"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}