PSEB Punjab Board Class 7 Science Textbook Solution Chapter 8 Wind, Storm and Cyclones Exercise Questions and Answers
Chapter 8 Wind, Storm and Cyclones
Q.1 Fill in the blanks:
1. Air exerts …………………
Answer:- Air pressure.
2. Moving air is called……………
Answer:- Wind.
3. Near Earth the …………….. air rises up and …………….. air comes down.
Answer:- warm, cooler.
4. Winds are generated due to …………….. heating of Earth.
Answer:- uneven heating of land and water.
5. The centre of a cyclone is called its……………..
Answer:- The eye.
Q.2 True or false:
1. A bicycle tube expands when we fill air in it.(T/F)
Answer:- False.
2. Air moves from a region of low pressure to high pressure.(T/F)
Answer:- False.
3. The speed of wind can be measured by an instrument called Anemometer.(T/F)
Answer:- True.
4. Thunder is a loud sound produced by lightning.(T/F)
Answer:- True.
5. We should ignore the cyclone warnings.
Answer:- False.
Q.3 Choose the correct option
1. Which of the following is not an example of air exerting pressure?
(a) Flying a kite
(b) Filling air in bicycle tube
(c) Filling air in balloon
(d) Hot air balloon
Answer:- d. Hot air balloon.
2. Moving air is called_______
(a) Wind
(b) Cyclone
(c) Lightening
(d) Strom
Answer:- a. Wind.
3. Which is the property of air?
(a) Expands on cooling
(b) Contracts on heating
(c) Expands on heating
(d) None of the above
Answer:- c. Expands on heating.
4. Winds are produced due to________
(a) Heating of air □
(b) Cooling on land □
(c) Heating of water □
(d) Uneven heating of land and water □
Answer:- d. Uneven heating of land and water.
5. High speed winds can cause________.
(a) Thunderstorm
(b) Cyclones
(c) Tornado
(d) All of above
Answer:- b. Cyclones.
Q.4 Match the column:
Answers :-
1. – c) Cyclone.
2. – d) Tornado.
3. – a) Air exerts pressure.
4. – b) Fast moving wind reduces pressure.
Q.5 Very short answer type questions
1. Which property of air is described by the inflatable balloon?
Answer:- Gas exerts pressure property of air is described by the inflatable balloon.
2. Which is lighter, Cold air or hot air?
Answer:- Warm air is lighter than cold air.
3. Which region of earth gets maximum heat from the Sun?
Answer:- The equator is the region of earth gets maximum heat from the sun.
4. Which winds bring rain in India?
Answer:- Southwest monsoon winds bring rain in India.
5. Name the instrument used for measuring the speed of wind?
Answer:- Anemometer is the instrument used for measuring the speed of wind.
Q.6 Short answer type questions:
1. Why are the holes made in hanging banners and hoardings?
Answer:- The fast moving air or high speed wind cannot blow the banners away if there
are holes in them the air will pass through the holes and will not exert pressure on the
banner and there will be no damage to it.
2. In which situation does the uneven heating of the earth produce winds?
Answer:- Winds are produced due to uneven heating of the Earth. It happens due to the
following reasons
(i) uneven heating between the equator and the poles.
(ii) Uneven heating of land and water.
3. Which winds blow from ocean to land in summer? What is their significance?
Answer:- Monsoon winds blow from ocean to land in summer. The monsoon wind carries a lot of water with them from the ocean which brings rains in India during the rainy season. Agriculture in India mainly depends on monsoon winds.
4. What is the difference between a thunderstorm and cyclone?
Answer:- As the name suggests, thunderstorms are gushes of wind that are accompanied by thunder and lightning. This is mainly caused due to the rising of hot air, similar to cyclones. However, unlike in cyclones, the rapid and continuous rise in warm air causes the wind to move even faster, thereby causing thunderstorms.
5. State effective measures to be taken in areas vulnerable to cyclones?
Answer:-
Effective Safety Measures :
There are some effective safety measures which should be taken in cyclone vulnerable areas.
(i) Effective Safety Measures to be taken by the Government : The following safety measures should be taken by the government:
(a) Coastal areas should be thickly planted with tall and indigenous species of plants, which checks the speed of wind.
(b) In coastal areas, ponds should be built to absorb excess of water.
(c) Cyclone shelters should be constructed in cyclone vulnerable areas.
(d) An efficient forecast measure should be adopted and the warnings should be communicated to the people of the affected area well in advance
(ii) Effective safety measures to be taken by the people :
The following safety measures should be taken by the people of the area:
(i) Do not ignore cyclone warnings.
(ii) If the area is regularly affected by the cyclone, it should be evacuated. (iii) Make
necessary arrangements to shift the valuable material, animals and people to safer places.
6. What is a tornado? Give two safety measures.
Answer:- A tornado is a violent storm, with strong rotating winds in a funnel shaped cloud. Its diameter can be from 1m to 1 Km. Due to very low pressure at the centre of the funnel, it pulls the dust, debris and even people and vehicles towards its centre.
Safety measures from a tornado:-
(i) Take shelter inside a room in the house without windows.
(ii) If a room without windows is not available then shut all the doors and windows.
Q.7 Long answer type questions:
1. Explain why does a tin can get crushed when water is boiled in it and after closing it cold water is poured on it?
Answer:- On pouring cold water the steam inside the can get school and changes the
water due to this there is less pressure of air inside the can then the outside atmospheric pressure so the can get crushed inverse due to the pressure of the outside air.
2. Explain with an activity that Air expands on heating.
Answer:- Materials Required: Boiling tube, beakers, balloon, tripod stand, hot water, ice cold water, cello tape.
Method: Take a boiling tube. Fix a balloon tightly over the neck of the boiling tube with the help of cello tape. Fill a beaker with hot water. Place the boiling tube with balloon in the beaker having hot water so that the balloon remains outside the hot water. Observe for 2-3 minutes for any change in the shape of the balloon. Take the tube out and let it cool down to the room temperature. Take some ice cold water in another beaker and place the tube with the balloon in cold water for 2-3 minutes. Observe the change in the shape of the balloon.
Observation: The balloon gets inflated after some time, when put in hot water and deflated when put in cold water.
Conclusion: When the boiling tube is placed in hot water, the air present in the boiling tube gets heated up and it expands which leads to the inflation of balloon. This shows that air expands on heating. If the boiling tube is cooled, the balloon gets contracted which shows that the air contracts on cooling. Air expands on heating and contracts on cooling.
3. How is a cyclone formed? Describe how a cyclone caused widespread destruction in Odisha in 1999.
Answer:- Cyclones can be very destructive as they are the strongest storms on earth.
Strong winds of cyclone pushes the sea water outwards with a great force. The extremely low pressure in the eye of cyclone lifts the sea water upwards. Sea water can rise up to a height of 3 to 12 meters. The sea water enters the low coastal areas and causes widespread destruction of life and property. The sea water also reduces the fertility of the soil.
The whole coastline of India is very vulnerable to the cyclones. The eastern coastal
regions like Odisha (Orissa), Chennai, Mangalore and Puri are most likely to be effected by the cyclones. The regions far away from the oceans like Punjab, Haryana and Delhi are not vulnerable to cyclones. In India, Odisha was affected by a cyclone on 18th October 1999. The speed of the wind was over 200 km/h and it destroyed 45,000 houses making 70,000 people homeless. Another cyclone hit Odisha on 29th October 1999 with the speed of wind 260km/h accompanied by 9 meter high waves. many people lost their lives and property worth crores was destroyed.
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