Students can download Class 8 Geography Chapter 3 Atmosphere Important Questions, KSEEB Class 8 Social Science Important Questions and Answers helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.
Karnataka State Syllabus Class 8 Social Science Geography Important Questions Chapter 3 Atmosphere
Question 1.
What is atmosphere?
Answer:
Atmosphere is a thin layer of gases, dust particles and water vapour surrounding the earth.
Question 2.
What is the importance of atmosphere?
OR
How is atmosphere important for life on earth?
Answer:
The atmosphere forms a protective boundary between outer space and earth’s surface. The thickness of the atmosphere is around 1,000 kms. Atmosphere is very important for all forms of life on earth. Different gases of the atmosphere help plants, animals and human beings. The atmosphere traps heat and makes earth a planet for all living beings.
Question 3.
Describe the composition of the atmosphere.
Answer:
The atmosphere is a mixture of different gases, dust particles and water vapour. The important gases in the atmosphere are Nitrogen – 78.08%, Oxygen – 20.94%, and the remaining 1% consists of Argon – 0.93%, Carbon dioxide 0.03%, Ozone 0.000005%, etc.
The atmosphere also contains dust particles which help in the formation of water droplets. The water vapour in the atmosphere is the source of clouds and precipitation. The atmosphere also traps heat and energy and has influence on the weather conditions of a place.
Question 4.
Name the different layers of the atmosphere. Draw a neat diagram showing the layers of the atmosphere.
Answer:
The atmosphere may be divided into five important layers on the basis of their characteristic features. These are troposphere, stratosphere, mesosphere, thermosphere (ionosphere) and exosphere.
Question 5.
What are the features of troposphere?
Answer:
Troposphere is the lowest layer of the atmosphere. It extends up to 18 kms. at the equator and 8 kms at the poles. This layer has all the atmospheric elements such as temperature, pressure, winds, clouds, rainfall, etc. All weather changes occur in the troposphere. Temperature and pressure decrease with the increase of altitude in the layer.
Question 6.
How is stratosphere useful?
OR
What is the importance of ozone layer?
Answer:
Stratosphere is the second layer of the atmosphere. This layer extends up to 50 kms. from the surface. It lies between troposphere and mesosphere. In this layer, ozone is the most important gas, which absorbs ultraviolet rays of the sun and protects all forms of life on earth. This layer is free from clouds and all forms of weather phenomena and provides ideal flying conditions for jet aircrafts.
Question 7.
Write a note on mesosphere.
Answer:
Mesosphere is the third layer in the Earth’s atmosphere. It extends up to 80 kms. from the surface and lies above the stratosphere. In this layer, temperature decreases with increase in altitude. This layer has the coldest temperature in the atmosphere.
Question 8.
Why is thermosphere also called ‘Ionosphere’?
Answer:
Thermosphere has very high temperature. Due to the very high temperature the gaseous atoms here get transformed into ions. Therefore, it is called ionosphere. The ions found in this layer help in reflecting radio waves.
Question 9.
What are the features of exosphere?
Answer:
Exosphere is the topmost layer of the atmosphere. In this layer elements of atmosphere are rare and pressure is extremely low.
Question 10.
Define weather.
Answer:
Weather is the atmospheric condition of a place at a given time.
Question 11.
What are the elements of weather?
Answer:
The elements of weather are – temperature, pressure, wind, humidity, clouds, rainfall, etc.
Question 12.
Distinguish between weather and climate.
Answer:
Atmospheric condition of a place at a given time is called weather. Whereas, the average atmospheric condition of an area over a long period of time is called climate.
Question 13.
Which is the main source of energy to the earth? How is this energy supplied?
Answer:
The Sun is the main source of energy to the earth. This energy is supplied in the form of heat through insolation.
Question 14.
What is insolation?
Answer:
Insolation is the incoming solar radiation from the sun to the earth.
Question 15.
How is temperature measured?
Answer:
Temperature is measured with the help of an instrument called ‘thermometer’. Centigrade and Fahrenheit are the important thermometers used to measure atmospheric temperature.
Question 16.
Name Hie factors that influence atmospheric temperature.
Answer:
Atmospheric temperature is influenced by factors like latitude, altitude or height, distance from the sea, wind, ocean currents, relief, clouds, rainfall, etc.
Question 17.
What is normal lapse rate?
Answer:
Normal lapse rate is the decreasing rate of temperature with the increase in altitude. The rate of decrease is 1°C for every 165 meters or 6.4°C for every 1000 meters height.
Question 18.
What is inversion of temperature?
Answer:
In some situations temperature also increases with increasing height. This takes place in mountain valleys during long winter nights with dear sky, dry air, no wind and snow covered surface.
Question 19.
Which are the temperature zones? Describe with a neat diagram.
Answer:
The distribution of temperature is not uniform on the earth’s surface. On the basis of insolation, the globe is divided into three temperature zones. They are torrid zone, temperate zone and frigid zone.
1. Torrid zone:
This is the zone of high temperature. This region is found on either side of the Equator, that is, between Tropic of Cancer (\({23}\ {1 / 2^{\circ}}\) N) and Tropic of Capricorn (\({23}\ {1 / 2^{\circ}}\) S). This region receives the direct rays of the sun.
2. Temperate zone:
In this region the temperature is moderate, that is, it is neither very hot nor very cold. It lies between \({23}\ {1 / 2^{\circ}}\) N to \({66}\ {1 / 2^{\circ}}\) N (Tropic of Cancer to Arctic Circle) and \({23}\ {1 / 2^{\circ}}\) S to \({66}\ {1 / 2^{\circ}}\) S (Tropic of Capricorn to Antarctic Circle).
3. Frigid zone:
It is the coldest zone. It lies between \({66}\ {1 / 2^{\circ}}\) N and 90° N (Arctic Circle to North Pole) and \({66}\ {1 / 2^{\circ}}\) S to 90° S (Antarctic Circle to South Pole). The temperature in this zone is very low due to slanting rays of the sun. In summer, temperature is slightly high and in winter the temperature is low.
Question 20.
Why is the temperature in the Frigid zone very low?
Answer:
The temperature in the frigid zone is very low due to the slanting rays of the sun.
Question 21.
What are isotherms?
Answer:
Isotherms are lines drawn on the map or globe connecting places having the same temperature.
Question 22.
Name the places in the world having highest and lowest temperatures.
Answer:
Al-Aziziya of Libya in Africa has recorded the highest temperature (average +58°C). Whereas, Verkhoyansk in Siberia has recorded the lowest temperature (average -24°C). Vostok in Antarctica is considered as the coldest place on earth with -89°C average temperature.
Question 23.
Name the places in India with the highest and the lowest temperatures.
Answer:
In India, Ganganagar in Rajasthan has recorded the highest temperature in summer (average +54°C). Leh in Jammu and Kashmir has recorded the lowest temperature in winter (average -10°C).
Question 24.
Which instrument is used to measure atmospheric pressure?
Answer:
Atmospheric pressure is measured by an instrument called Barometer. The unit used is milibar (mb).
Question 25.
What is atmospheric pressure? What factors influence atmospheric pressure?
Answer:
Air has weight and it exerts pressure. This is called atmospheric pressure. Atmospheric pressure is influenced by factors like temperature, rotation of the earth, altitude, water vapour, etc.
Question 26.
Describe the relationship between atmospheric pressure and temperature.
Answer:
Temperature is the most important factor that influences atmospheric pressure. The regions that have high temperature have low atmosphericpressure due to expansion of air while the regions of low temperature have high pressure due to contraction of air. Thus, temperature and pressure are inversely related. Atmospheric pressure decreases with increase in altitude.
Question 27.
Which are the major pressure belts of the earth? Show them in a neat diagram.
Answer:
The major pressure belts of the earth are:
- The equatorial low pressure belt.
- North sub-tropical high pressure belt.
- South sub-tropical high pressure belt.
- North sub-polar low pressure belt.
- South sub-polar low pressure belt.
- North Polar high pressure belt and
- South Polar high pressure belt.
Question 28.
What is Doidrum? Where is it found?
OR
Which region is called ‘Doidrum’ or ‘belt of calm’?
Answer:
Equatorial low pressure belt lying between 0° and 5° North and South of the equator has Warm and hot air throughout the year. This is a calm region with very little wind. Hence, it is known as ‘Doidrum’ or ‘belt of calm’.
Question 29.
Which region is popularly called ‘Horse latitude’?
Answer:
The north sub-tropical high pressure belt lying between 30° and 35° north latitudes is popularly called ‘horse latitude’.
Question 30.
What are isobars?
Answer:
Isobars are imaginary lines drawn on the map or globe connecting places having the same pressure.
Question 31.
What are winds? How are they formed?
Answer:
Wind is the horizontal movement of air on the surface of the earth. Winds blow on the earth due to rotation of the earth and difference in pressure.
Question 32.
What are the uses of’Wind Vane’ and ‘Anemometer’?
Answer:
The wind vane is an instrument used to show the direction of the wind. The anemometer is an instrument used to measure the speed of the wind.
Question 33.
Which are the different types of winds?
Answer:
Winds are classified into four major types. They are planetary winds, seasonal winds, local winds, and cyclones and anticyclones.
Question 34.
What are planetary winds? Name the different types of planetary winds.
Answer:
Planetary winds are winds that blow more or less in the same direction throughout the year. They are also called permanent winds or prevailing winds or regular winds. These winds are of three types, i.e., trade winds, anti-trade winds and polar winds.
Question 35.
What are trade winds?
Answer:
Trade winds are winds that blow from sub-tropical high pressure belts to equatorial low pressure region. The trade winds in the northern hemisphere blow from North-east to South-west (North East Trade Winds), and in the southern hemisphere they blow from South-east to North¬west (South East Trade Winds).
Question 36.
What are Westerlies or anti-trade winds?
Answer:
Anti-trade winds are winds that blow from sub-tropical high pressure belts to sub-polar low pressure belts. These blow from south-west to north-east in the northern hemisphere and north-west to south-east in the southern hemisphere. These winds are also called westerlies.
The westerlies of the southern hemisphere are very strong over the oceans. Hence they are called ‘Roaring forties’ (40° south latitude), ‘Furious fifties’ (50° south latitude) and ‘Shrieking sixties’ (60° south latitude)
Question 37.
What are the features of Easterlies or Polar winds?
Answer:
Polar winds are also called Easterlies. These winds blow from polar high pressure belts to sub-polar low pressure belts. They blow from north-east to south-west in the northern hemisphere and south-east to north-west in the southern hemisphere. These are cold dry winds blowing from the polar ice caps.
Question 38.
What are seasonal winds? Which are the seasonal winds blowing over India?
Answer:
Seasonal winds or periodic winds are winds that change their direction periodically or seasonally. The monsoon winds of India are the typical seasonal winds. In India, South-west monsoon windy blow from June to September and North-east monsoon winds blow from late September to middle of December.
Question 39.
What are local winds? Give two examples.
Answer:
Periodic winds or local winds are the result of variation in local temperature, pressure and humidity which are in turn attributed to the formation of air currents, crossing mountain ranges, valleys and other relief features. The important periodic and local winds are land breeze, sea breeze, mountain breeze and valley breeze. A few other winds are Loo, Chinook, Fohn, Mistral, Sirocco, Brick Fielder, Blizzard, etc.
Question 40.
What are cyclones and anti-cyclones? How are they formed?
Answer:
Cyclones and anti-cyclones are winds that blow due to great variation in pressure. These are temporary but sometimes dangerous and destructive. Cyclone is a small low pressure area in the centre surrounded by high pressure.
The winds blow spirally towards the low pressure area. In the northern hemisphere the direction of cyclonic winds is anti-clockwise or counter-clockwise, and in the southern hemisphere it is clockwise.
Anti-cyclone is a high pressure area at the centre with winds blowing outwards, towards the low pressure area. In the northern hemisphere the direction of anti-cyclone wind is clockwise and in the southern hemisphere it is anti-clockwise.
Question 41.
Which are the two types of cyclones?
Answer:
Cyclones are of two types – tropical cyclones and temperate cyclones.
Question 42.
What is humidity? What instrument is used to measure it?
Answer:
Humidity is the amount of water vapour or moisture present in the air. Humidity is measured by using an instrument called ‘Hygrometer’ or ‘Psychrometer’.
Question 43.
What are the different types of humidity?
Answer:
Humidity is expressed in different ways. They are absolute humidity, relative humidity and specific humidity.
Question 44.
Explain the different types of humidity.
Answer:
Absolute humidity, relative humidity and specific humidity are the three types of humidity.
- Absolute humidity: This refers to the total amount of water vapour present in a given volume of air. Here, temperature is not taken into consideration.
- Relative humidity: It is the ratio between the actual amount of water vapour present in the air and the maximum amount of water vapour the air can hold at that temperature.
- Specific humidity: It is the actual amount of water vapour present in a given mass of air.
Question 45.
What are clouds?
Answer:
Clouds are masses of small water drops or ice crystals formed by the condensation of water in the atmosphere, usually at a considerable height above the earth’s surface,
Question 46.
Mention the different types of clouds.
Answer:
Based on their shape and the height at which they occur, clouds are classified as – Stratus, Cumulus, Cirrus and Nimbus.
Question 47.
What are the features of Stratus clouds?
Answer:
Stratus clouds are usually low clouds occufring at less than 2 km. height. They appear as thin Sheets or layers of large extent. Stratus clouds are associated with fair weather.
Question 48.
What are Cumulus clouds?
Answer:
Cumulus clouds are cauliflower-shaped clouds of great vertical extent. The base of the cumulus clouds is nearly horizontal, while the top has a dome-shaped appearance. These are popularly called ‘wool packs’. Cumulus clouds are rain-bearing clouds.
Question 49.
Mention the features of Cirrus clouds.
Answer:
Cirrus clouds are the highest clouds in the atmosphere. These clouds have a feathery or fibrous appearance. They indicate fair weather and often give brilliant sunset. They look like patches of cotton fibres floating in the air. They are popularly called ‘mare’s tail’ or ‘witch’s broom’.
Question 50.
What are the features of Nimbus clouds?
Answer:
Nimbus clouds are rain clouds which 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. The nimbo-stratus are thick, heavy, rain-bearing clouds.
Question 51.
What is rainfall? How is it measured?
Answer:
Precipitation in the form of water droplets is called rainfall. The total amount of rain received in a given area during a given time is measured by a rain gauge in millimeters or inches.
Question 52.
What are the different types of rainfall?
Answer:
Rainfall is of three types. They are Convectional rainfall, Orographic rainfall and Cyclonic rainfall.
Question 53.
What is convectional rainfall? How does it occur?
Answer:
The rain caused by the process of convection is called convectional rainfall. In areas of high temperature air rises up due to heating. This rising air gets cooled and saturated and
condensation takes place and later rainfall occurs. Convectional rainfall is very common in the equatorial region and also in tropical regions in summer. In the equatorial region, convectional rainfall is called ‘afternoon rain’, as it mostly occurs in the afternoon. It is accompanied by thunder and lightning.
Question 54.
What is orographic rainfall?
Answer:
Orographic rainfall is also called mountain rainfall or ‘relief rainfall’. When moisture-laden air is obstructed by a mountain barrier, the air is forced to move up. As the air rises upwards it.
gets cooled and saturated. Further cooling of this air causes condensation resulting in orographic rainfall or mountain rainfall.
Question 55.
What is meant by ‘rain shadow region’?
Answer:
The windward side of the mountain receives more rainfall, while the leeward side of the mountain receives less rainfall. This leeward side of the mountain is generally called ‘rain shadow area’.
Question 56.
How does cyclonic rainfall occur?
Answer:
In a cyclone the air blows spirally inwards. In tropical cyclones the air rises upwards in a circular movement. So, condensation takes place to cause heavy rainfall. The temperate cyclonic rain is also called frontal rain. When the warm air mass and cold air mass meet, warm air being lighter is forced to rise over the heavier cold air. The warm air, after rising, cools and condenses, resulting in rainfall.
Question 57.
On what factors does distribution of rainfall on the earth depend?
Answer:
Distribution of rainfall on the earth depends on the location and the climatic condition of that region.
Question 58.
Which are the regions of heavy rainfall in the world?
Answer:
The most important regions of heavy rainfall in the world are the equatorial region, the eastern margins of sub-tropical belts, the western margins between 40° and 60° north and south latitudes.
Question 59.
Which are the regions of scanty rainfall in the world?
Answer:
The most important regions of scanty rainfall in the world are the polar areas, the western margins of sub-tropical regions and the tropical and temperate deserts.
Question 60.
Which is the wettest place on earth?
Answer:
Mawsynram in Meghalaya in India has recorded 1140 cm rainfall per year. This is the highest in the world. Therefore, it is considered as the wettest place on earth.
Question 61.
What is meteorology?
Answer:
The scientific study of weather is called meteorology.
Question 62.
What is climatology?
Answer:
The scientific study of climate is called climatology.
Question 63.
Mention the factors that affect the climate of a place.
Answer:
The factors that influence the climate of a place or region are latitude, altitude, winds, distance from the sea, distribution of land and water bodies, ocean currents, etc.
Question 64.
Define the following:
Answer:
1. Ionosphere:
Thermosphere lies above the mesosphere. It has very high temperature. Due to the very high temperature the gaseous atoms here get transformed into ions. Therefore, it is called ionosphere.
2. Normal lapse rate:
Normal lapse rate is the decreasing rate of temperature with the increase in altitude.
3. Torrid zone:
Torrid zone is the zone of high temperature as it receives the direct rays of the sun. This region is found on either side of the Equator, that is, between Tropic of Cancer (23%° N) and Tropic of Capricorn (23%° S).
4. Horse latitude:
Horse latitude is the north sub-tropical high pressure, belt lying between 30° and 35° north latitudes.
5. Orographic rainfall:
When moisture-laden air is obstructed by a mountain barrier, the air is forced to move up. As the air rises upwards it gets cooled and saturated. Further cooling of this air causes condensation resulting in orographic rainfall or mountain rainfall or relief rainfall.
6. Climatology:
The scientific study of climate is called climatology.
Multiple Choice Questions
Question 1.
The thin layer of gases, dust particles and water vapour surrounding the earth is called
(A) atmosphere
(B) biosphere
(C) hydrosphere
(D) environment.
Answer:
(A) atmosphere
Question 2.
The thickness of the atmosphere is about _________ kms.
(A) 100
(B) 250
(C) 500
(D) 1000
Answer:
(D) 1000
Question 3.
78 percent of the atmosphere is made up of
(A) oxygen
(B) nitrogen
(C) ozone
(D) argon.
Answer:
(B) nitrogen
Question 4.
The __________ in the stratosphere absorbs ultraviolet rays of the sun and protects all forms of life on earth.
(A) nitrogen
(B) oxygen
(C) ozone
(D) argon.
Answer:
(C) ozone
Question 5.
Thermosphere is also called
(A) mesosphere
(B) ozonosphere.
(C) exosphere
(D) ionosphere.
Answer:
(D) ionosphere.
Question 6.
Normally, with the increase in altitude the temperature
(A) does not change
(B) increases
(C) decreases
(D) gets balanced.
Answer:
(C) decreases
Question 7.
The area lying between Tropic of Cancer and Tropic of Capricorn is called
(A) Frigid zone
(B) Torrid zone
(C) Temperate zone
(D) Ionosphere.
Answer:
(B) Torrid zone
Question 8.
The temperature in the Frigid zone is very low because of
(A) slanting sun rays
(B) direct sun rays
(C) sun rays not reaching
(D) reflection of sun rays.
Answer:
(A) slanting sun rays
Question 9.
The lowest winter temperature in India is recorded at _________ in Jammu and Kashmir.
(A) Srinagar
(B) Gulmarg
(C) Leh
(D) Anantnag.
Answer:
(C) Leh
Question 10.
Lines drawn on a map or a globe connecting places having the same temperature are called
(A) isobars
(B) isotherms
(C) barometer
(D) milibars.
Answer:
(B) isotherms
Question 11.
The equatorial low pressure belt is also called –
(A) doldrum
(B) ionosphere
(C) torrid zone
(D) horse latitude.
Answer:
(A) doldrum
Question 12.
The ‘Roaring forties’ belongs to the category of
(A) seasonal winds
(B) local winds
(C) trade winds
(D) anti-trade winds.
Answer:
(D) anti-trade winds.
Question 13.
Cyclones are also called
(A) Roaring forties
(B) local winds
(C) planetary winds
(D) typhoons.
Answer:
(D) typhoons.
Question 14.
The amount of water vapour and moisture present in the air is called
(A) clouds
(B) ice flakes
(C) humidity
(D) temperature
Answer:
(C) humidity
Question 15.
Which clouds are also known as ‘mare’s tail?
(A) Nimbus
(B) Cirrus
(C) Cumulus
(D) Stratus
Answer:
(B) Cirrus
Question 16.
Precipitation in the form of water droplets is called
(A) rainfall
(B) snowfall
(C) dew
(D) Frost
Answer:
(A) rainfall
Question 17.
The ‘afternoon rain’ occurs normally in
(A) Polar region
(B) Temperate zone
(C) Equatorial region
(D) Torrid zone
Answer:
(C) Equatorial region
Question 18.
The place in Karnataka known as ‘Mawsynram of South India’ is
(A) Agumbe
(B) Karwar
(C) Mangalore
(D) Madikeri
Answer:
(A) Agumbe
Fill In the Blanks
- The two major gases found in the atmosphere are nitrogen and oxygen.
- The lowest layer of the atmosphere is troposphere.
- The average atmospheric pressure at the sea level is 1013.25 mb.
- The westerlies are also called anti trade winds.
- The scientific study of weather is called meteorology.
- Ozone absorbs ultraviolet rays of the sun.
- The lines drawn on a map connecting places with the same temperature are called isotherms.
- the coldest place on earth is vostok in antarctica
- Air pressure is measured in milibars using a barometers.
- The imaginary lines drawn on a map connecting places having the same pressure are isobars.
- The direction of the wind is shown by an instrument called Wind vane
- The amount of water vapour and moisture present in the air is called humidity
- The clouds which are found in the lowest part of the atmosphere are nimbo stratus.
- The clouds known as wood packs are cumulus
- The scientific study of climate is called climatology.
- The place in Chitradurga which is considered the driest place in Karnataka is Nayakanahatti
- The driest region on the earth is Atacama desert
- Plain clouds are called Stratus clouds.
Match The Following
Question 1.
| A | B |
| a. Japan | 1. Hurricane |
| b. America | 2. Cyclone |
| c. Australia | 3. Typhoon |
| d. India | 4. Tsunami |
| e. Russia | 5. Willy Willies |
| 6. Whirlpool |
Answer:
a – 4, b – 1, c – 5, d – 2, e – 6.
Question 2.
| A | B |
| a. Troposphere | 1. Topmost layer of the atmosphere |
| b. Stratosphere | 2. Coldest temperature in the atmosphere |
| c. Mesosphere | 3. Lowest layer of the atmosphere |
| d. Thermosphere | 4. Ozone is found here |
| e. Exosphere | 5. Absorbs all sun rays |
| 6. Ionosphere |
Answer:
a – 3, b – 4, c – 2, d – 6, e – 1.