1st PUC Geography Question Bank Chapter 5 Atmosphere

Students can Download 1st PUC Geography Chapter 5 Atmosphere Questions and Answers, Notes Pdf, 1st PUC Geography Question Bank with Answers helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.

Karnataka 1st PUC Geography Question Bank Chapter 5 Atmosphere

1st PUC Geography Atmosphere Text Book Questions and Answers

I. Answer the following in a word or a sentence each.

Question 1.
Define Atmosphere.
Answer:
The atmosphere is the thin layer of vapour, gases and dust particles around the Earth and extends to 1,600 km above the earth.

Question 2.
What is the percentage of Nitrogen in the Atmosphere?
Answer:

• Nitrogen – 78%
• Oxygen – 21%

Question 3.
Why is Carbon dioxide important in the Atmosphere?
Answer:
Carbon-di-oxide is needed for plants. It traps the sun’s heat in the atmosphere and acts as an insulating agent, which makes the earth warm during nights.

Question 4.
Which layer of atmosphere is called ‘Weather manufacturer’?
Answer:
Troposphere.

Question 5.
In which layer do you find Aurora?
Answer:
Thermosphere.

Question 6.
What is Stratopause?
Answer:
Stratopause is the boundary between the stratosphere and mesosphere.

Question 7.
Which is the coldest layer in the Atmosphere?
Answer:
Mesosphere.

Question 8.
Define Insolation.
Answer:
Insolation is the heat (temperature) received by the Earth from the sun and is responsible for life and activity on the Earth.

Question 9.
What is Convection?
Answer:
Convection is the transmission of heat from one part of a liquid or gas to another by movement of the particles. Air rises upwords due to convection from the heat of the earths surface.

Question 10.
Mention the average atmospheric pressure of the Earth.
Answer:
The average atmospheric pressure at the sea level is 1013.25mb.

Question 11.
How many pressure belts are there in the globe?
Answer:
There are seven pressure belts on the globe

Question 12.
Define Doldrums.
Answer:
Doldrums is the equatorial trough or low pressure belt and extends from 0° to 5° N/S of Equator. As it receives direct sun rays throughout the year, the atmospheric pressure is low as air heats up and rises. The trade winds converge in this region and receives regular convectional rainfall.

Question 13.
Where do we find ‘Horse latitudes’?
Answer:
Horse latitudes is the sub tropical high pressure belt between 25° to 3 5° N/S of the equator. This belt is formed due to the rotation of the earth. The descending air currents cool the region and form high Atmospheric pressure the trade winds and anti-trade winds originate in this belt.

Question 14.
Name the instrument used to measure speed of the Wind.
Answer:
Anemometer.

Question 15.
What is ITCZ?
Answer:
Inter-tropical convergent zone (ITCZ). Is the region of convergence of trade winds.

Question 16.
Where do we see ‘Roaring Forties’?
Answer:
Roaring forties are found around 40° south latitude

Question 17.
Why are Tropical cyclones more dangerous?
Answer:
Tropical cyclones cause heavy Rainfall with high-velocity winds hence they are highly dangerous and devastating.

Question 18.
What is Rain shadow region?
Answer:
When winds begin to descend over the leeward side of the mountain the temperature steadily increases resulting in dry air and – fonn ‘Rainshadow region’. The rainfall in this region is scarce.

Question 19.
Which instrument is used to measure the amount of Rainfall?
Answer:
Rain Gauge.

Question 20.
Mention any two factors that determine the climate of a place.
Answer:

• Latitude
• Distance from the sea.

II. Answer the following in two or three sentences each.

Question 1.
Mention any two components of Atmosphere.
Answer:

• Gases
• Water vapour.

Question 2.
Name any four important gases present in the atmosphere.
Answer:

• Nitrogen 78%
• Oxigen 21%
• Carbon-di-oxide
• Hydrogen

Question 3.
Why is Troposphere called ‘Region of Mixing’?
Answer:
The word Troposphere literally means ‘the region of mixing’ ‘Tropos’ is a Greek word which means ‘Mixing’ or ‘Turbulence’. All changes in weather conditions takes place inthis layer. Features like thunder lightning, rainbow and precipitation occur jn this region. Temperature, pressure, winds, cloudsis experienced in this region.

Question 4.
What is the role of Ionosphere in the Atmosphere?
Answer:
As the temperature increases drastically in the Thermosphere due to the absorption of heat from the sun the gas molecules break up to form Ions. Ions are positively or negatively Charged particles: which help in the transmission of Radio waves and reflect them back to the earth and helps in radar and navigation communication. Moreover the ionosphere protects us from meteors.

Question 5.
Mention the features of Inversion of Temperature.
Answer:
Features of Inversion of Temperature.

1. Temperature increases with the increase in temperature
2. Inversion ofTemperature is common during winter season when there is less cloudiness, slow movement of winds and clear skies in mountain valleys.

Question 6.
Who do pressure belts shift?
Answer:
The pressure belts move (50N and south) in response to the apparent migration of the sun. Between December and June the sun moves northwards and between June and December it moves south ward. Therefore the pressure belts follow the annual migration of sun to wards the north and south.

Question 7.
Name the two important Trade winds.
Answer:

1. North East Trade (NET) winds
2. South East Trade (SET) winds

Question 8.
How is Sea breeze formed?
Answer:
During daytime land gets heated more quickly than the adjacent sea. The air over the land gets heated and rise upwards to produce a low pressure region. Since the pressure over sea is compartively high, the warm air of the land beging light rushes up wards allowing the air from sea to eather in these winds blowing over the land from the sea are called ‘Sea Breezes.

Question 9.
Mention the features of a Cyclone.
Answer:
Features of Cyclone:

1. Cyclone is a small lo w pressure are a in the center surrounded by high pressure.
2. Winds blow spirally towards the low pressure area and form convergence of winds.
3. The direction of cyclonic winds in anti-clock-wise and in the northern hemisphere and clockwise in the southern hemisphere.
4. Cyclones are of two types:
   • Tropical cyclones
   • Temperate Cyclones.

Question 10.
Mention any four uses of tides.
Answer:
Orographic Rainfall:
or mountain rainfall or Relief rainfall- occurs when the moisture-laden winds are forced to ascend and loses temperature, resulting in condensation and rainfall. Rain falls on the windward side of the mountain.

III. Answer the following.

Question 1.
Explain the topgraphy of the Ocean floor with a diagram.
Answer:
The atmosphere extends to about 1,600 km, from the surface of the Earth. But 99% of its mass is found within 32 km. The atmosphere has its multi-layered structure consisting of the following basic layers Troposphere, Stratosphere, Mesosphere, Thermosphere and Exosphere.

Troposphere – Region of Mixing:
The term Troposphere literally means “the region of mixing’. It is derived from the Greed word ‘Tropos’ means ‘mixing’ or ‘turbulence’. The troposphere is the lowest layer in which life exists. All changes in wather conditions take place in this layer. It is known as ‘Weather manufacture’.

Temperature, pressure, winds, clouds and other special features like thunder, lightning, rainbow and precipitation are common in this layer. This layer serves as a good means of transport for passenger aircraft. This is due to the fact that the density of air decreases with height and so the heat absorbed is lost.

It extends to a height of 8 km at the poles and 18km at the Equator. The average height of the troposphere is 12 km. Temperature decreases with an increase in height at an average rate of 10°C/ 165m or 6.4°C/1000m is called normal Lapse Rate. Tropopause is the boundary between Troposphere and Stratosphere.

Stratosphere:
This is the second layer of the atmosphere. It extends to about 50km from the surface of the Earth. It is free from water vapor and dust particles. There are no clouds or turbulence in the air, thus, this layer provides ideal conditions for flying of jet aircraft.

Temperature increases due to the absorption of the ultraviolet radiation of the Sun by ozone. This region is rich in Ozone which is vital for life on the Earth. The ozone layer is found between 5 to 20 km. Stratopause is the boundary between Stratosphere and Mesosphere,

Mesosphere:
The mesosphere extends to a height of 80km from the surface of the Earth, it is the ‘clodest’ layer of the atmosphere. The gases are too thinto absorb the sun rays. The temperature starts decreasing with increase in altitude and reaches up to minus 100°C at the height of 80km. Mesopause is the boundary between Mesosphere and Thermosphere.

Thermosphere:
This layer extends from 80 km to 600 km from the surface of the Earth. In this layer temperature rises drastically because, the gas molecules in his layer absorb the x-rays and shortwave radiation of the Sun. This results in the break up of the gas molecules into positively and negatively charged particles.

These electrically charged particles are known as “Ions” and hence this layer is known as Ionosphere. Radio waves transmitted from the Earth are reflected back to the Earth by this layer. It helps in Radar, Navigator communication. The ionosphere protects us from meteors. It also forms Aurora or Natural bands oflight. They are Aurora Borealis andAuroraAustralis.

Exosphere:
The region beyond the Thermosphere is called Exosphere. It extends to about 1,000 km and the gravity of the Earth is too weak in this leayer Magnetosphere is found above this layer.

Question 2.
Briefly explain the factors affecting the distribution of temperature.
Answer:
Factors affecting the distribution of Temperature:
Normally the temperature distribution is recorded horizontally and vertically. Horizontal distribution temperature is determined by latitude. The general decline in temperature from the equator towards the poles is one of the most fundamental and best-known facts. The horizontal distribution of temperature is the function of numerous other physical factors.

They are: Latitude, Altitude, Distance from the Sea, Ocean currents, Wind, Clouds & Rainfall, the slope of the land, vegetation and Nature of the Soil Of the various climatic elements, temperature, pressure, winds precipitation have far-reaching effects, whether it be horizontally from the equator to the poles or vertically from sea level to high altitudes.

Latitudes:
Places close to the equator have higher temperature and are warmer then places away from the equator. This is because the Sun rays reach the Earth after passing through the layers of the atmosphere. In the low latitudes, the Sun rays reach the Earth after passing through the players of the atmosphere.

In the low latitudes the Sun rays are direct and have to travle a lesser extent through the atmosphere. Honce, the heat of these rays is more intense. But in high latitudes, the Sun rays are slanting and have to pass through a greater extent of the atmosphere. These rays rays lose heat and so the areas in the high latitudes are not very hot as compared to the equatorial regions.

Altitude:
The height of a place above the mean sea level is the altitude of that place. The atmosphere is mostly heated by various heat mostly heated by various heat processes. Air is cooler at higher altitudes than near the Earth’s surface. So the places near the Earth’s surface are warmer than places higher up.,

This is because air near the surface is denser and contains gases like carbon dioxide, water vapour and other gases. So their capacity ofheat absorption is more than in the upper layers. Temperature decreases with increase in height at an average rate pf IOC/ 165 m or 6.40C/1000 m.

Sometimes temperature increases with the increase in height known as ‘Inversion of ‘Temperature’. This feature is common druing winter season, less cloudiness, slow movement of winds, clear sky in the mountain valley.

Distance from the Sea:
This factor also influences on the distribution of temperature and differential heating of land and water. Land gets heated faster compared to water. Water takes longer time to get heated and to cool than land. Hence druing the day when the land gets heated quikly.

Water takes longer time and remains cool. Therefore, druing the day time land gets more heat than the surrounding water bodies (sea and ocean). The coastal areas are coller and wetter than the inland areas.

Ocean currents:
Ocean currents increase or decrease the temperature of the Earth’s surface. Warm ocean currents along the coast make the coastal areas warmer and cold currents reduce the temperature and cools the coastal areas.

Warm currents can be noticed on the eastern margins of the continents in the middle latitude, while it is the cold currents flow at the western margins of the continents, eg. Gulf Stream a warm current, increases the temperature in the eastern coast if U.S.A and California cold current decreases the temperature ofthe western coast of U.S.A.

Winds:
Winds that blow from the lower latitudes are warm and make the places warmer. One the other hand, wind that blow from the higher latitudes are cold and make the places cooler. Winds that blow from the sea bring patiently of rain especially if they are warm winds. While offshore winds hardly any rain.

Clouds:
During the day clouds prevent Insolation from reaching the Earth’s surface. Clouds also prevent the escape of terrestrial radiation during the night. Clear sky permits Insolation readily the daytime and allow the rapid escape of terrestrial radiation during the night.

Isotherms:
Lines drawn on the map or globe joining the places having the same temperature.

Question 3.
Describe the major pressure belts of the world with a neat diagram.
Answer:
Major Pressure Belts:
There are seven pressure belts on the globe. They are Equatorial low-pressure belt (lbelt), sub-tropical high-pressure belts (2 belts), sub-polar low-pressure belts (2 belts) and polar high-pressure belts (2 belts).

1. Equatorial Trough or Low-Pressure belt:
This belt extends from 0° to 5° North aud South of the Equator. It receives direct rays of the sun almost throughout the year. Hence the air becomes hot, expands and rises. Thus a belt of low pressure is created in this region. It is a ‘belt of calm’ with very little wind, therefore it is known as ‘Doldrum’ (Equatorial calm). This is a region of convergence of trade winds. It receives regular conventional rainfall.

2. Sub-tropical High-Pressure belt:
This belt is found between 25° to 35° North and South of the equator. The formation of this belt is associated with rotation of the Earth and descending air currents. The warn air rises at the equator, blows to higher altitude and diverts towards poles. The wind cools down as it rises and spreads towards the poles.

Gradual cooling makes this air heavy and sinks down to the surface at 30° North and South of the equator. This results in the formation of high-pressure belt. The trade winds and anti trade winds originate in this belt. This belt is also called ‘Horse Latitudes’. There are two Sub-tropical high-pressure belts.

3. Sub-polar low-pressure belt:
This belt lies between 60° to 70° North and South of the equator. A low-pressure belt is created mainly due to the rotation of the Earth, which swings the bulk of the air towards the equator. These are the areas of storminess, especially in winter. There are two subpolar low-pressure belts

• North Sub-polar low-pressure belt and
• South Sub-polar low-pressure belt.

4. Polar high-pressure belt:
The two polar regions experience low temperature throughout they year. Thus the cold air sinks down because of its greater density. Sinking of cold air in the polar region results in high pressure. Polar high oressure belt extends from 80° to 90° latitudes in both the hemispheres. The polar high pressure blets record extremely cold weather condition so air is dense and heavy.
There are two polar high-pressure belts

• North Polar high-pressure belt and
• South polar high-pressure belt.

Question 4.
Explain the planetary winds with the help of diagram.
Answer:
Planetary winds:
Planetary winds are also called permanent winds. These winds blow regularly from high pressure to low pressure belts in a fixed direction throughout the year. They play a major role in climate change, desert formation, guide navigation routes etc., There are three types of planetary winds. They are:

1. Trade winds
2. Westerlies or Antitrade winds and
3. Polar winds.

1. Trade winds:
Trade winds are also called the Tropical Easteries’. These winds originate and blow from Sub-tropical high pressure belts to Equatorial low pressure belt. The word ‘trade’ is derived from the Latin word ‘trado’ means, constant direction (phrase-to blow trades). There are two types of trade winds.

• North East Trade (NET) winds
• South East Trade (SET) winds.

Trade winds are also called Easterlies. North East trade winds from northern hemisphere and South east trade winds from southern hemisphere meet near the Equator. This region is the converging zone of trade winds known as ‘Inter- tropical convergent zone’(ITCZ). This regioa has different characteristics-low pressure, Variable winds and calm conditions and convergence of trade winds.

2. Antitrade winds:
These winds orginate and blow from Sub-tropical high pressure belts to Sub-polar low pressure belts. These are from South west to North east direction in northern hemisphere and North west to South east in the southern hemisphere. Therefore, they are called ‘Westerlies’. The direction of these winds are opposite to trade winds. Hence, they are known as ‘Antitrade winds’.

In the northern hemisphere because of the presence of vast land masses with varied relief features large scale disturbance are formed by Antitrade winds. In the southern hemisphere they are more regular and blow with grat velocity because of vast expanse of ocean water. These winds cause great problem to navigation in the southern hemisphere.
The important westerlies in the southern hemisphere are:

• ‘Roaring Forties’ found around 40° south latitude.
• ‘Furious Fifties’ Found around 50° south latitude.
• ‘Shrieking sixties’ or ‘Screeching sixties’ or Screaming sixties’ around 60° south latitude.

3. Polar winds:
These are extremely cold winds blowing from polar high-pressure belts to Sub-polar low-pressure belts. Polar winds are more regular and blow without much variation. However they are strong in the winter season (coldwave) than in summer.

They blow from North east to South west in the northern hemisphere and South east to North west in the southerb hemisphere (similar to trade winds), as such they are also known as ‘Polar Easterlies’.

Question 5.
What is Rainfall? Explain the types of rainfall with neat diagrams.
Answer:
Rainfall:
is the natural process of condensation through which gaseous form of water is converted into liquid water droplets. It occurs due to cooling of saturated air mass, warm and moist air mass risingupward warm air rising over cold air, sufficient humidity in the air and condensation etc.,
Types of Rainfall:
According to the process of formation, nature and features, three of rainfall are recognized.

1. Convectional Rainfal
2. Orographic Rainfall
3. Cyclonic Rainfall.

1. Convectional Rainfall:
The rain caused by the process of convection is called convectional rainfall. In the areas of high temperature, air rises up due to heating. This rising air cools, gets saturated, as a result condensation takes place and later rainfall occurs. Conventional rainfall is very common in the Equatorial region and also in the Tropical regions summer. This rain is accompanied by thunder and lightning.

2. Orographic Rainfall:
It is the most common and widespread form of rainfall in the world. It is also called ‘Mountain Rainfall’ or ‘Relief Rainfall’ During this rain the moisture laden winds are forced to ascend over the mountains in their path. As the wind rises, it expands and loses temperature.

This results in condensation, leading to rainfall. This rainfall isf found in the windward side of the mountain and is heavy. In the leeward side of the mountain, as the wind begins to descend, the temperature steadily increases resulting in dry air by forming ‘Rain’ Shadow Region’.

3. Cyclonic rainfall:
The cyclonic rainfall is most common in the temperate region. The rainfall caused with a cyclone or depression is known as Cyclonic rainfall The winds take a circular movement in the regions where warm and cold air masses meet.
Rain Gauge:
The amount of rainfall received, is measured by an instrument called Rain gauge.