NCERT Exemplar Class 7 Science Chapter 8 Winds, Storms and Cyclones

NCERT Exemplar Class 7 Science Chapter 8 Winds, Storms and Cyclones are part of NCERT Exemplar Class 7 Science. Here we have given NCERT Exemplar Class 7 Science Solutions Chapter 8 Winds, Storms and Cyclones.

NCERT Exemplar Class 7 Science Solutions Chapter 8 Winds, Storms and Cyclones.

Multiple Choice Questions

Question 1.
A fire alarm usually detects smoke in case of fire. Where should such an alarm be placed in a room?
(a) Near the door
(b) On the floor
(c) On any wall
(d) On the ceiling
Solution:
(d)

Question 2.
Four schematic diagrams are shown in figure to depict the direction of sea breeze. Which of them gives the correct direction?

Solution:
(c) Air above the land gets heated and rises up and is replaced by the cool air from the sea giving rise to sea breeze.

Question 3.
Figure shows a child blowing air with a straw near the opening of another straw which has its other end in a soft drink bottle. It was observed that the level of the soft drink in the straw rises up as soon as air is blown over its open end. Which one of the following best explains the reason for rise in level of the drink?

(a) Slowing of air decreases pressure over the opening of the straw.
(b) The straw of the soft drink bottle collapses when air is blown over its open end.
(c) Blowing of air warms up the air inside the straw.
(d) Blowing of air increases the pressure on the surface of soft drink in the bottle.
Solution:
(a)

Question 4.
Following are precautions one must take in case a storm is accompanied by lightning.
(i) Do not take shelter under a tree.
(ii) Do not take shelter under an umbrella with a metallic end.
(iii) Do not take shelter in open garages, storage sheds, etc.
(iv) Do not take shelter in a bus in the open. Which one of these is not correct?
(a) (i)
(b) (ii)
(c) (iii)
(d) (iv)
Solution:
(d)

Question 5.
Which of the following place is most likely to be affected by a cyclone?
(a) Mumbai
(b) Puri
(c) Goa
(d) Porbandar
Solution:
(b)

Question 6.
A curtain is hanging at the entrance of a room. A long corridor runs at right angles to the door, that is parallel to the curtain. If a strong wind blows along the corridor, the curtain will
(a) get pushed inside the room.
(b) get pushed outside the room.
(c) get collected towards one end/swirled.
(d) remain unaffected.
Solution:
(b)

Very Short Answer Type Questions

Question 7.
Why is Chandigarh unlikely to be affected by a cyclone?
Solution:
Chandigarh is unlikely to be affected by a cyclone as it is not near to the sea/ocean.

Question 8.
Name the ocean which is mainly responsible to bring rain bearing monsoon winds to Kerala coast in June every year?
Solution:
Indian ocean is mainly responsible to bring rain bearing monsoon winds to Kerala coast in June every year.

Question 9.
Fill in the blanks.
(i) Air around us exerts____.
(ii) The moving air is called_____.
(iii) The main cause of wind movement is uneven ____ on the earth.
(iv) High speed wind can cause cyclone in regions of _____pressure.
Solution:
(i) pressure
(ii) wind
(iii) heating
(iv) low

Question 10.
State whether the following statements are
True or False:
(i) If wind flows from land to the ocean, then it is daytime.
(ii) A very high pressure system, with very high speed wind surrounding it forms a cyclone.
(iii) The coast line of India is not vulnerable to cyclones.
(iv) Warm air is lighter than cool air.
Solution:
(i) False
(ii) False
(iii) False
(iv) True

Question 11.
To expel hot air out of the kitchen, ‘A’ has an exhaust fan fitted on the window of her kitchen and ‘B’ has a similar exhaust fan fitted on the
wall near the ceiling of her kitchen. Which of the exhaust fan will expel the hot air more effectively? Explain why?
Solution:
B’s exhaust fan will expel the hot air more effectively because hot air rises up, so being at a greater height than A’s exhaust fan, volume of air that will reach to B’s exhaust fan will be more.

Question 12.
Why is it advisable not to shut all the doors and windows during a storm?
Solution:
It is advisable not to shut all the doors and windows during a storm in order to avoid the roof of the house getting blown away due to the low pressure created by heavy wind.

Question 13.
A flat in Mumbai with a balcony facing the sea has some clothes hung on a clothes line in the balcony. Towards which direction the clothes will be blown in the afternoon?
Solution:
The clothes will be blown towards the house due to sea breeze blowing towards the land.

Question 14.
Figure shows a diagrammatic representation of trees in the afternoon along a sea coast. State on which side is the sea; A or B? Give reasons for your choice.

Solution:
Sea is on B side as in the afternoon, wind is blowing from sea to the land known as sea breeze.

Question 15.
A flag mounted on a flag post near the sea coast flutters in the direction of sea. At what time of the day does this happen – at midnight or in the afternoon?
Solution:
At midnight because of land breeze.

Short Answer Type Questions

Question 16.
Match column I with column II. There can be more than one match.

Solution:
(a) (ii) and (iv)
(b) (i) and (iii)

Question 17.
Paheli kept an empty bottle made of plastic inside a refrigerator. After few hours, when she opened the refrigerator she found the bottle had collapsed. Explain the possible reason.
Solution:
The air inside the bottle contracts due to low temperature, hence the bottle collapses due to the outside pressure.

Question 18.
When strong/high-speed wind blows, an umbrella held upright at times gets upturned. Explain the reason.
Solution:
Umbrella gets upturned when strong/ high speed wind blows because high speed wind passing over the umbrella creates low pressure.

Question 19.
Suggest some precautions to be taken to prevent the roof of a tin sheet from flying away during a fierce wind storm.
solution:
To prevent the roof of a tin sheet from flying away during a fierce wind storm, following mentioned precautions should be taken:
(i) Put heavy stones, bricks, etc. on it.
(ii) Screw it tightly.
(iii) Do not shut all the doors and windows.

Long Answer Type Questions

Question 20.
Describe an activity to demonstrate that warm air is lighter than cool air.
solution:
Take two paper bags or empty paper cups of the same size. Hang the two bags in the inverted position on the two ends of a metal or wooden stick.

Tie a piece of thread in the middle of the stick. Hold the stick by the thread as in a balance. Put a burning candle below one of the bags as shown in the figure.
We observe that the bag below which candle is placed, is pushed up. It is due to the reason that on heating, the air expands and occupies more space and hence becomes lighter. Hence, it proves that the warm air is lighter than cool air.

Question 21.
The picture in figure shows tree line along the sea coast on an island near the equator. As shown, the tree tops are permanently bent in one direction. Are the trees bent towards the sea or away from it? Explain.

solution:
In the coastal regions of an island near the equator, heating and cooling of air is a regular phenomenon. During daytime, the land gets heated up quickly compared to the water in the sea. Air above the land gets heated and rises up and is replaced by the cool air from the sea giving rise to sea breeze. This sea breeze makes the trees to bend towards the land.

Question 22.
Identify the names of six natural phenomena from the following word diagram given in figure

solution:

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