Thursday, 10 November 2011

CBSE Class VII (7th) Geography -Chapter 4. Air - Solved Exercises

Question1.Answer the following questions.
Q(i).What is atmosphere?
Answer.A huge blanket of air by which our earth is surrounded is called atmosphere.
The atmosphere have following layers :
(a) Troposphere.
(b)Stratosphere
(c) Mesosphere
(d) Thermosphere
(e) Exosphere



Out of these atmospheric layers, Troposphere is the most important layer of the atmosphere, which directly support life on this planet.
Our Atmosphere and its Layers


Q(ii).Which two gases make the bulk of atmosphere?
Answer.(a) Nitrogen. (b) Oxygen.

Q(iii).Which gas creates green house effect in atmosphere?
Answer. Carbon dioxide.

Q(iv).What is weather?
Answer. Wheather is hour-to-hour,day to day conditions of the atmosphere.

Q(v). Name three types of rainfall?
Answer.(i) The convectional rainfall. (ii)The orographic rainfall. and (iii)The cyclonic rainfall.

Q(vi). What is air pressure?
Answer. Air pressure is defined as the pressure exerted by the weight of air on the earth's surface.

Question2.Tick the correct answer:
Q(i) Which of the following gases protects us from harmful sun rays?
(a) Carbondioxide. (b)Nitrogen. (c)Ozone.

Answer:(c) Ozone.

Q(ii) The most importent layer of the atmosphere is.
(a) Troposphere. (b)Thermosphere. (c) Mesosphere

Answer:(a) Troposphere.

Q(iii) Which of the following layers of atmosphere free from clouds?
(a) Troposphere. (b)Stratosphere. (c) Mesosphere

Answer:(b) Stratosphere.

Q(iv).As we go up the layers of the atmosphere, the pressure.
(a) Increases. (b) Decreases. (c) Remain same.

Answer: (b) Decreases.

Q(v)When precipitation comes down to the earth liquid form,it is called:
(a) cloud. (b) Rain. (c) Snow.

Answer: (b) Rain.

Question3. Match the following:
1Trades winds.(a)Seasonal.
2Loo.(b)Horizental movement of air.
3Mansoon. (c)Permanent wind.
4Wind.(d)Local wind
Answer.


1Trades winds.(c)Permanent wind.
2Loo.(d)Local wind .
3Mansoon. (a)Seasonal.
4Wind.(b)Horizental movement of air.

Question 4.Give resons.
Q(i) Wet clothes take longer time to dry on a hhmid day?
Answer. Because sun rays fall vertical on the equator while slanting on the poles.

Q(ii). Amount of insolation decreases from equator towards poles?
Answer. Because on a humid day,there is more water in ait than a sunny day.So, air can soak less weater from wet clothes i.e., rate of evaporation decreases.

Question 5.For fun.
Q(i). Solve this crossword puzzle with the help of given clues(on page no.28):

Answer.

 

HC
UL
LMOW
ROIUPEEPAL
CARBONDIOXIDEAT
IAINTM
NRTSHO
OYEXOSPHERES
MLRP
EAIRFH
TTOXYGEN
NEEMWINDGR
ROE
OZONE
CYCLONE

Q(ii).Make a weather calender for one weak.Use pictures or symbols to show different types of weather.You can use more than one symbol in a day, If the weather changes.For example,the sun comes out when rain stops. An example is given below:
Answer.

DaySymbol of Weather Conditions Weather Conditions
Sunday

Sunny day
Monday

Cloudy day
Tuesday

Rainy day
Wednesday

Snowfall.
Thursday

Hail Storm.
Friday
Tropical-Storm
Saturday

Thunder Shower
CBSE Class VII (7th) Geography -Chapter 4.  Air  - Solved Exercises

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