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Air Class 7 Extra Questions Geography Chapter 4
Class 7 Geography Chapter 4 Extra Questions And Answers Question 1.
What is atmosphere?
Answer:
The huge blanket of air by which our earth is surrounded is called atmosphere.
Class 7 Geography Chapter 4 Extra Questions Question 2.
Why is atmosphere essential for human beings? Explain.
Answer:
- It provides us the air we breathe.
- It protects as from the harmful rays of the sun.
- It makes the temperature of the earth liveable.
Ncert Class 7 Geography Chapter 4 Extra Questions Question 3.
Which two gases are found in the atmosphere in abundance?
Answer:
- Nitrogen,
- Oxygen.
Air Class 7 Questions And Answers Question 4.
Name the gases which are found in the atmosphere in lesser quantities?
Answer:
- Carbon dioxide,
- Helium,
- Ozone,
- Argon and
- Hydrogen.
Class 7 Geography Air Extra Questions Question 5.
Write the percentages of different gases found in the atmosphere.
Answer:
- Nitrogen – 71%
- Oxygen – 21%
- Carbon dioxide – 0.3%
- Argon – 0.93%
- All others – 0.04%.
Air Class 7 Extra Questions And Answers Question 6.
Which two gases can influence the atmosphere to a large extent?
Answer:
- Carbon dioxide,
- Ozone.
Class 7 Geography Chapter 4 Air Question Answer Question 7.
Why is carbon dioxide called a greenhouse gas?
Answer:
Carbon dioxide traps the heat radiated from the earth and creates a greenhouse effect. Therefore, it is called a greenhouse gas.
Class 7 Air Extra Questions Question 8.
What is global warming?
Answer:
The quantity of carbon dioxide increases due to factory smoke or car fumes, and the heat retained increases the temperature of the earth. This is called global warming.
Air Class 7 Worksheet With Answers Question 9.
How is ozone gas important to us?
Answer:
Ozone gas forms a protective layer around the earth. It absorbs the harmful ultraviolet radiations of the sun.
Extra Questions For Class 7 Geography Chapter 4 Question 10.
Write the effects of global warming.
Answer:
- It causes the snow in coldest parts of the world to melt.
- Sea level rises, causing submergence of coastal areas.
- Drastic changes in the climate lead to the extinction of some plants and animals in the long run.
Class 7 Geography Ch 4 Extra Questions Question 11.
What are the causes of ozone layer’s depletion? How would it affect the human beings?
Answer:
- Chemicals given out by refrigerators and air conditioners are responsible for the depletion of ozone layer.
- In the absence of ozone layer, the ultraviolet radiations of the sun will reach the earth’s surface and cause serious damage to our skin and eyes.
Class 7 Geography Chapter 4 Questions And Answers Question 12.
Name the five layers of the atmosphere.
Answer:
- Troposphere,
- Stratosphere,
- Mesosphere,
- Thermosphere and
- Exosphere.
Air Chapter Class 7 Extra Questions Question 13.
Ionosphere is the part of which layer?
Answer:
Ionosphere is the part of thermosphere.
Chapter 4 Geography Class 7 Extra Questions Question 14.
Why troposphere is the most important layer of the atmosphere?
Answer:
- The air we breathe exists in the troposphere.
- Almost all the weather phenomena, like rainfall, fog and hailstorm, occur in this layer.
Class 7 Geography Chapter Air Extra Questions Question 15.
Why is stratosphere the most ideal for flying aeroplanes?
Answer:
Stratosphere is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying aeroplanes.
Question 16.
Write one important feature of stratosphere and mesosphere each.
Answer:
- Stratosphere contains a layer of ozone gas, which protects us from the harmful effect of the sun’s rays.
- Meteorites burn, up in mesosphere on entering from the Space.
Question 17.
Write two main features of thermosphere.
Answer:
- In thermosphere, temperature rises very rapidly with increasing height.
- Radio waves transmitted from the earth are reflected back to the earth by thermosphere.
Question 18.
Which is the uppermost layer of the atmosphere? Name two gases found here.
Answer:
Exosphere is the uppermost layer of the atmosphere. Helium and hydrogen gases are found here.
Question 19.
What is weather?
Answer:
Hour-to-hour, day-to-day condition of the atmosphere is called weather.
Question 20.
What is climate?
Answer:
The average weather condition of a place for a longer period of time represents the climate of that place.
Question 21.
What is temperature? Also, mention its measuring unit.
Answer:
The degree of hotness and coldness of the air is known as temperature. The standard unit of measuring temperature is degrees Celsius.
Question 22.
Write the boiling and freezing points of water on Celsius scale.
Answer:
Freezing point of water on Celsius scale – 0°C
Boiling point of water on Celsius scale – 100°C.
Question 23.
Who invented the following temperature scales.
(i) Celsius,
(ii) Fahrenheit,
(iii) Kelvin,
(iv) Reaumur.
Answer:
| Temperature scales | Inventor |
| 1. Celsius | Anders Celsius |
| 2. Fahrenheit | Daniel Gabriel Fahrenheit |
| 3. Kelvin | Lord William Thomson Kelvin |
| 4. Reaumur | Rene Antoine Ferchault de Reaumur |
Question 24.
What is insolation?
Answer:
Insolation is the incoming solar energy intercepted by the earth.
Question 25.
Why are the poles covered with snow?
Answer:
The amount of insolation decreases from the equator towards the poles. Therefore, temperature remains low at the poles and they are covered with snow.
Question 26.
Why is the temperature in cities much higher than that of villages? Give two reasons.
Answer:
- The concrete and metals in buildings and the asphalt of roads get heated up during the day. This heat is released during the night.
- The crowded high rise buildings of the cities trap the warm air and thus raise the temperature of the cities.
Question 27.
What is air pressure?
Answer:
Air pressure is the pressure exerted by the weight of air on the earth’s surface.
Question 28.
Write the weather conditions of low pressure and high-pressure areas.
Answer:
- Low pressure is associated with cloudy skies and wet weather.
- High pressure is associated with clear and sunny skies.
Question 29.
Why do astronauts wear special protective space suits?
Answer:
Astronauts wear special protective space suits filled with air because there is no air pressure on the moon. The counter pressure exerted by the body of the astronaut would make the blood vessels burst. They would bleed to death.
Question 30.
Following instruments are used to measure which weather elements —
(i) Barometer,
(ii) Thermometer,
(iii) Wind Vane,
(iv) Rain Gauge.
Answer:
(i) Barometer is used to measure atmospheric pressure.
(ii) Thermometer is used to measure the temperature.
(iii) Wind Vane is used to know the direction of the wind.
(iv) Rain gauge is used.to measure the amount of rainfall.
Question 31.
How are temperature and pressure of an area inversely related to each other? Explain.
Answer:
- (i) The areas where temperature is high the air gets heated and rises. This creates a low-pressure area.
- (ii) The areas where temperature is low, the air is cold. It is therefore heavy. Heavy air sinks and creates a high-pressure area.
Question 32.
What is wind?
Answer:
The movement of air from high-pressure area to low-pressure area is called wind.
Question 33.
Name the three types of winds.
Answer:
- Permanent winds,
- Seasonal winds and
- Local winds.
Question 34.
What are permanent winds? Give examples.
Answer:
Permanent winds blow constantly throughout the year in a particular direction, e.g., trade winds, westerlies and easterlies.
Question 35.
What are seasonal winds?
Answer:
Seasonal winds change their direction in different seasons, e.g., monsoon winds.
Question 36.
What are local winds?
Answer:
Local winds blow only during a particular period of the day or year in a small area, e.g., land and sea breeze.
Question 37.
What is humidity and humid day?
Answer:
Moisture in the air at any time is known as. humidity. When the air is full of water vapour, we call it a humid day.
Question 38.
Write four forms of precipitation.
Answer:
- Rain,
- Snow,
- Sleet and
- Hail.
Question 39.
Which place in India receives the highest amount of rainfall in the world?
Answer:
Mawsynram in Meghalaya receives the highest amount of rainfall in the world.
Question 40.
What is rain?
Answer:
Precipitation that comes down to the earth in liquid form is called rain.
Question 41.
Name the three types of rainfall.
Answer:
- Convectional rainfall,
- Orographic rainfall and
- Cyclonic rainfall.
Question 42.
How does water vapour precipitate? Explain.
Answer:
- As the air gets warmer, its capacity to hold water vapour increases.
- When water vapour rises, it starts cooling. The water vapour condenses causing formation of droplets of water.
- Masses of such water droplets form clouds.
- When these droplets of water become too heavy to float in air, then they come down a precipitation.
Multiple Choice Questions (MCQs)
1. Which one of the following statements is true about the atmosphere?
(а) Huge domain of water.
(b) Solid crust of the earth.
(c) Huge blanket of air that surrounds our earth.
(d) Flora and fauna of the earth.
Answer:
(c) Huge blanket of air that surrounds our earth.
2. The atmosphere protects us from;
(а) meteors
(b) thunderstorms
(c) heavy rainfall
(d) harmful effects of the sun’s rays.
Answer:
(d) harmful effects of the sun’s rays.
3. Which one of the following gases is found in bulk in the atmosphere?
(a) Nitrogen
(b) Helium
(c) Hydrogen
(d) Argon.
Answer:
(a) Nitrogen.
4. What is the percentage of carbon dioxide in the atmosphere?
(a) 21%
(b) 0.04%
(c) 78%
(d) 0.03%
Answer:
(d) 0.03%.
5. Which one of the following gases is required for the survival of the plants?
(a) Oxygen
(b) Nitrogen
(c) Argon
(d) Helium.
Answer:
(b) Nitrogen.
6. Which one of the following is known as a greenhouse gas?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Ozone.
Answer:
(c) Carbon dioxide.
7. Which one of the following statements is false about oxygen?
(a) About 21% of oxygen is present in the atmosphere.
(b) Humans and animals take oxygen from the air to breathe.
(c) Green plants produce oxygen during photosynthesis.
(d) Increasing level of oxygen in the atmosphere can cause global warming.
Answer:
(d) Increasing level of oxygen in the atmosphere can cause global warming.
8. The weather and climate of the earth get affected by;
(a) increasing volume of argon.
(b) increasing volume of Carbon dioxide.
(c) increasing volume of nitrogen.
(d) increasing volume of ozone.
Answer:
(b) increasing volume of Carbon dioxide.
9. Which one of the following is different from the other three, with reference to the layers of the atmosphere?
(a) Lithosphere
(b) Troposphere
(c) Stratosphere
(d) Exosphere
Answer:
(a) Lithosphere.
10. In which one of the following layers, almost all the weather phenomena take place?
(a) Mesosphere
(b) Exosphere
(c) Troposphere
(d) Stratosphere
Answer:
(c) Troposphere.
11. Ozone gas is found in which one of the following layers?
(а) Troposphere
(b) Stratosphere
(c) Thermosphere
(d) Mesosphere.
Answer:
(b) Stratosphere.
12. Which one of the following statements is false about mesosphere?
(a) It lies above the stratosphere.
(b) It extends up to the height of 80 km.
(c) Meteorites burn up in mesosphere on entering from the space.
(d) It is the uppermost layer of the atmosphere.
Answer:
(d) It is the uppermost layer of the atmosphere.
13. Which one of the following layers is helpful in radio transmission?
(a) Exosphere
(b) Thermosphere
(c) Mesosphere
(d) Troposphere.
Answer:
(b) Thermosphere.
14. Which is the uppermost layer of the atmosphere?
(a) Stratosphere
(b) Mesosphere
(c) Exosphere
(d) Troposphere.
Answer:
(c) Exosphere.
15. Which one of the following statements truly defines the word climate?
(a) The average weather condition of a place for a longer period of time.
(b) A hot and humid weather conditions of a place.
(c) It is the day to day condition of the atmosphere.
(d) It can be changed dramatically.
Answer:
(a) The average weather condition of a place for a longer period of time.
16. Which one of the following instruments is used to measure the temperature?
(a) Wind vane
(b) Rain gauge
(c) Thermometer
(d) Barometer.
Answer:
(c) Thermometer.
17. The atmospheric pressure is measured by;
(a) Rain gauge
(b) Barometer
(c) Wind vane
(d) Thermometer.
Answer:
(b) Barometer.
18. Which one of the following terms is used for the incoming solar energy intercepted by the earth?
(a) Reradiation
(b) Condensation
(c) Evaporation
(d) Insolation.
Answer:
(d) Insolation.
19. Which one of the following statements is false about the air pressure?
(a) The air pressure does not exist at every place.
(b) The pressure exerted by the weight of air on the earth’s surface.
(c) The air pressure is highest at sea level and decreases with height.
(d) Low pressure is associated with cloudy skies and wet weather.
Answer:
(a) The air pressure does not exist at every place.
20. Which one of the following terms is used for the movement of air from high-pressure area to low pressure area?
(a) Ocean current
(b) Wind
(c) Sun’s rays
(d) Water vapours.
Answer:
(b) Wind.
21. Which one of the following is different from the other three, with reference to the types of winds?
(a) Permanent wind
(b) Seasonal wind
(c) Californian current
(d) Local wind.
Answer:
(c) Californian current.
22. Which one of the following is not associated with the permanent winds?
(a) Trade wind
(b) Loo
(c) Easterlies
(d) Westerlies
Answer:
(b) Loo.
23. Which one of the following winds change their direction in different seasons?
(a) Trade winds
(b) Easterlies
(c) Westerlies
(d) Monsoon winds.
Answer:
(d) Monsoon winds.
24. Which one of the following winds is hot and dry local wind of Northern Plains of India?
(a) Khamsin
(b) Kaal Baisakhi
(c) Loo
(d) Mango shower.
Answer:
(c) Loo.
25. Moisture in the air at any time, is known as;
(a) humidity
(b) evaporation
(c) condensation
(d) radiation.
Answer:
(a) humidity.
26. Which one of the following terms is used for the precipitation comes down on the earth in the liquid form?
(a) Clouds
(b) Hail storm
(c) Sleet
(d) Rain.
Answer:
(d) Rain.
27. On the basis of mechanism, the rainfall can be divided into three types. Which one of the following is different from them?
(а) Snowfall
(b) Orographic rainfall
(c) Cyclonic rainfall
(d) Convectional rainfall
Answer:
(а) Snowfall.