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Term 1 — Chapter 2

Weather and Climate

Class 7 - Around the World Geography Solutions


Quick Quiz 1

Question 1

Name three elements of weather.

Answer

The three elements of weather are:

  1. Air temperature
  2. Atmospheric pressure
  3. Humidity

Question 2

The climate of a place remains the same while the weather keeps changing. True or false?

Answer

True

Question 3

The incoming solar radiation is called ............... .

Answer

The incoming solar radiation is called insolation .

Question 4

An area of (low/high) pressure is created by warm air.

Answer

An area of low pressure is created by warm air.

Question 5

Name the pressure belts on the earth.

Answer

The pressure belts on the earth are:

  1. Equatorial low pressure belt
  2. Subtropical high pressure belts
  3. Sub-polar low pressure belts
  4. Polar high pressure belts

Quick Quiz 2

Question 1

The horizontal movement of air is called ............... .

Answer

The horizontal movement of air is called wind .

Question 2

The (monsoon/trade) winds are planetary winds.

Answer

The trade winds are planetary winds.

Question 3

The land breeze blows during the day. True or false?

Answer

False

Corrected Statement — The land breeze blows during the night.

Question 4

What is humidity?

Answer

The amount of water vapour present in air is called humidity.

Question 5

Name a rain-bearing cloud.

Answer

Cumulonimbus is a rain-bearing cloud.

Tick the correct answers

Question 1

Which of these is effective in heating the atmosphere?

  1. sunshine
  2. terrestrial radiation
  3. advection
  4. insolation

Answer

terrestrial radiation

Question 2

How many low pressure belts are there on the earth's surface?

  1. two
  2. three
  3. four
  4. seven

Answer

three

Question 3

The Harmattan wind blows over the north-western part of

  1. Australia
  2. Asia
  3. Europe
  4. Africa

Answer

Africa

Question 4

Which of these is not a form of condensation?

  1. drizzle
  2. cloud
  3. dew
  4. fog

Answer

drizzle

Question 5

............... rainfall occurs in the equatorial region.

  1. Orographic
  2. Frontal
  3. Convectional
  4. Cyclonic

Answer

Convectional

Write true or false

Question 1

The torrid zone receives minimum insolation.

Answer

False

Corrected Statement — The torrid zone receives maximum insolation.

Question 2

The atmospheric pressure is the highest in the mountains.

Answer

False

Corrected Statement — The atmospheric pressure is the highest at the mean sea level.

Question 3

The planetary winds blow in a particular direction throughout the year.

Answer

True

Question 4

The dust particles in the air help in condensation.

Answer

True

Question 5

The orographic rainfall is common in the belt of the westerlies.

Answer

False

Corrected Statement — The frontal rainfall is common in the belt of the westerlies.

Fill in the blanks

Question 1

The frigid zone lies between the ............... and the ............... in the southern hemisphere.

Answer

The frigid zone lies between the Antarctic Circle (66.5° S) and the South Pole (90° S) in the southern hemisphere.

Question 2

The atmospheric pressure is measured in ............... .

Answer

The atmospheric pressure is measured in Millibar(mb).

Question 3

The sea breeze is a ............... wind.

Answer

The sea breeze is a periodic wind.

Question 4

The ............... clouds have hair-like appearance.

Answer

The cirrus clouds have hair-like appearance.

Question 5

The ice pellets that fall with rain are called ............... .

Answer

The ice pellets that fall with rain are called hailstones.

Give reasons for the following

Question 1

Land breeze blows during the night.

Answer

At night, due to radiation, land is cooler than the adjoining sea. This leads to the development of a high pressure area over the land and the cooler wind from the land blows towards the sea. This wind is called the land breeze.

Question 2

The leeward side of mountains is the rainshadow area.

Answer

When a mountain comes in the path of moisture-laden winds, moist air ascends along the slope of windward side which leads to cooling followed by condensation and precipitation. On the leeward side of the mountain, the air descends and becomes warmer. Thus, the leeward side gets less rainfall and is known as the rainshadow area.

Answer these questions

Question 1

What is the difference between weather and climate?

Answer

Weather is defined as the state of air temperature, atmospheric pressure, humidity, precipitation and winds in the atmosphere at a given place and time. The conditions of different elements of weather keep changing from time to time and from place to place. Thus, the change in weather is a continuous phenomenon. Climate is defined as the average overall condition of the air temperature, atmospheric pressure, humidity, precipitation and winds over a large region and for a long period of time. The climate of a place remains more or less the same year after year.

Question 2

Define solar radiation, insolation and terrestrial radiation.

Answer

Solar radiation — The sun radiates heat and light energy. This is called solar radiation.

Insolation — The amount of solar radiation received by the earth's surface is called insolation.

Terrestrial radiation — The earth's surface absorbs maximum insolation during the day. At night, the heat which was absorbed during the day, is radiated back. This is called terrestrial radiation.

Question 3

What is atmospheric pressure? What are the causes for the variations in the atmospheric pressure?

Answer

The atmosphere exerts its weight as pressure on the earth's surface. This is called atmospheric pressure.

The variations in the atmospheric pressure on the earth's surface is due to:

  1. Temperature of the air
  2. Density of the air
  3. Height of a place above the mean sea level
  4. Amount of moisture present in the air.

Question 4

Write three differences between planetary and periodic winds.

Answer

Three differences between planetary and periodic winds are:

Sl.
No.
Planetary WindsPeriodic Winds
1.Planetary winds blow constantly in a particular direction throughout the year.Periodic winds blow in a definite direction during a particular period of the day or year.
2.Planetary winds originate due to the presence of permanent high pressure and low pressure belts on the earth's surface.Periodic winds are caused due to unequal heating and cooling of the earth's surface.
3.Planetary winds do not have any tendency to reverse their direction periodically.Periodic winds have tendency to reverse their direction periodically.

Question 5

Distinguish between absolute humidity and relative humidity.

Answer

Sl.
No.
Absolute HumidityRelative Humidity
1.It is the actual amount of water vapour present in air.It is the ratio between the actual amount of water vapour present in the air at a given temperature and the maximum capacity of the air to hold moisture at that temperature.
2.It determines the amount of precipitation.It tells about the possibility of precipitation.
3.It is expressed in grams per cubic metre.It is expressed in percentage.

Question 6

Name the different forms of condensation and precipitation.

Answer

The different forms of condensation are:

  1. Dew — In winters, the moist air comes in contact with cold surfaces and the water vapour condenses on them. The water droplets thus formed are called dew.
  2. Frost — If the temperature falls below freezing point, tiny ice crystals are formed in place of water droplets. This is called frost.
  3. Clouds — When water droplets condense around dust or smoke particles in the air, the mass thus formed is called cloud.

The different forms of precipitation are:

  1. Rain — When precipitation occurs in the form of water drops, it is called rain.
  2. Drizzle — It is a light continuous rainfall in which the rain drops are of very small size.
  3. Hail — It is a kind of solid precipitation consisting of balls or irregular lumps of ice, each of which is called a hailstone.
  4. Snow — When air temperature is below freezing point, the water vapour present in clouds condenses to form tiny ice crystals called snow.
  5. Sleet — When snow and rain fall together, it is called sleet.

Question 7

What is rain? Classify rainfall and explain convectional rainfall with a labelled diagram.

Answer

When precipitation occurs in the form of water drops, it is called rain and it is the most important form of precipitation. Rainfall can be classified into three types. They are:

  1. Orographic rainfall
  2. Convectional rainfall
  3. Cyclonic rainfall

Convectional rainfall — When air comes in contact with the hot surface of the earth, it gets heated, becomes light and rises in form of air current. After the warm air current reaches the upper layers of the atmosphere, it expands and loses heat. This leads to condensation and the formation of cumulus clouds. These clouds give sudden and heavy rainfall accompanied by thunder and lightning. Convectional rainfall occurs every day in the equatorial region.

What is rain? Classify rainfall and explain convectional rainfall with a labelled diagram. Around the World Geography Solutions ICSE Class 7.
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