NCERT Solutions for Class 7 Science Chapter 8 Winds, Storms And Cyclones are provided here with simple step-by-step explanations. These solutions for Winds, Storms And Cyclones are extremely popular among Class 7 students for Science Winds, Storms And Cyclones Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the NCERT Book of Class 7 Science Chapter 8 are provided here for you for free. You will also love the ad-free experience on Meritnation’s NCERT Solutions. All NCERT Solutions for class Class 7 Science are prepared by experts and are 100% accurate.
Page No 42:
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
Answer:
Air above the fire gets heated and rises up in case of fire, thus a fire alarm should be placed on the ceiling to detect the fire.
Hence, the correct answer is option (d).
Page No 42:
Question 2:
Four schematic diagrams are shown in he given figure to depict the direction of sea breeze. Which of them gives the correct direction?
| (a) |  |
(b) | |
| (c) | |
(d) | |
Answer:
During the day, the land gets heated faster than the water. The air over the land becomes hotter and rises up. The cooler air from the sea rushes in towards the land to take its place. The warm air from the land moves towards the sea to complete the cycle as shown in option (c). The air from the sea is called the sea breeze.
Hence, the correct answer is option (c).
Page No 42:
Question 3:
Given in the 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) Blowing 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.
Answer:
Blowing of air decreases pressure over the opening of the straw, which makes the level of drink rise.
Hence, the correct answer is option (a).
Page No 43:
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)
Answer:
It is safe to take shelter in a bus in case of lightning, because lightning gets path to move to ground through the metallic body of bus.
Hence, the correct answer is option (d).
Page No 43:
Question 5:
Which of the following place is most likely to be affected by a cyclone?
(a) Mumbai
(b) Puri
(c) Goa
(d) Porbandar
Answer:
Puri lies near the coastal areas, so it is most likely to be affected by a cyclone.
Hence, the correct answer is option (b).
Page No 44:
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.
Answer:
Strong wind creates low pressure in the corridor i.e. outside the room and high pressure inside the room. Due to this pressure difference, the curtain will get pushed outside the room.
Hence, the correct answer is option (b).
Page No 44:
Question 7:
Why is Chandigarh unlikely to be affected by a cyclone?
Answer:
Chandigarh is very far from the sea. That is why, it is unlikely to be affected by a cyclone.
Page No 44:
Question 8:
Name the ocean which is mainly responsible to bring rain bearing monsoon winds to Kerala coast in June every year?
Answer:
Indian Ocean
Page No 44:
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.
Answer:
(i) Air around us exerts Pressure.
(ii) The moving air is called wind.
(iii) The main cause of wind movement is uneven heating on the earth.
(iv) High speed wind can cause cyclone in regions of low pressure.
Page No 44:
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.
Answer:
(a) False
(b) False
(c) False
(d) True,
Page No 44:
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?
Answer:
Hot air rises up and exhaust fan B is at higher height than exhaust fan A, so exhaust fan B will expel the hot air more effectively.
Page No 44:
Question 12:
Why is it advisable not to shut all the doors and windows during a storm?
Answer:
Air pressure gets reduced over the roof when high speed wind blows and there will be higher pressure below the roof. Due to this pressure difference, the roof can get blown away during storms. That is why, it is advisable not to shut all the doors and windows during a storm.
Page No 44:
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? Explain.
Answer:
Sea breeze blows from sea towards the land, so clothes will be blown towards the house.
Page No 45:
Question 14:
In the given 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.
Answer:
Sea must be on the side B as the wind is blowing from sea towards the land during the daytime.
Page No 45:
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?
Answer:
At midnight, land breeze blows from land towards sea. So, a flag mounted on a flag post near the sea coast flutters in the direction of sea at midnight.
Page No 45:
Question 16:
Match Column I with Column II. There can be more than one match.
| Column I | Column II |
| (a) On heating air | (i) descends |
| (b) On cooling air | (ii) expands |
| (iii) contracts | |
| (iv) rises |
Answer:
| Column I | Column II |
| (a) On heating air | (ii) expands, (iv) rises |
| (b) On cooling air | (i) descends, (iii) contracts |
Page No 45:
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.
Answer:
Due to low temperature, air inside the bottle contracts. And hence the bottle collapses due to the pressure outside the bottle.
Page No 45:
Question 18:
When strong/high speed wind blows, an umbrella held upright at times gets upturned. Explain the reason.
Answer:
High speed wind passing over the umbrella creates low pressure, due to which an umbrella gets upturned
Page No 45:
Question 19:
Suggest some precautions to be taken to prevent the roof of a tin sheet from flying away during a fierce wind storm.
Answer:
Precautions to be taken to prevent the roof of a tin sheet from flying away during a fierce wind storm:
1. Put heavy objects on it.
2. Screw it tight
Page No 46:
Question 20:
Describe an activity to demonstrate that warm air is lighter than cool air.
Answer:
Activity to demonstrate that warm air is lighter than cool air:
1. Take two paper bags of the same size and hang them in inverted position on the two ends of a stick.
2. In the centre of the stick, tie a thread and hang the stick through thread to balance it.
3. Place a burning candle below one of the two paper bags.
4. As the air above the candle becomes warm, it rises up and it pushes the bag above the candle upward.
Page No 46:
Question 21:
The picture in the given 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.
Answer:
Heating and cooling of air is a regular phenomenon in the coastal regions of an island near the equator. During daytime, the land gets heated up faster as compared to the water in the sea. Hot air above the land rises up and is replaced by the cool air from the sea. This gives rise to sea breeze. Thus, the trees will bend towards the land due to sea breeze.
Page No 46:
Question 22:
Identify the names of six natural phenomena from the following word diagram given as in the given figure
| G | C | H | T | H | T | E | N | M | R |
| R | C | Y | H | O | O | N | C | Z | P |
| V | L | O | U | E | R | O | E | R | T |
| A | N | C | N | A | N | N | L | C | L |
| H | T | H | D | B | A | D | A | P | I |
| L | U | N | E | K | D | C | Y | D | G |
| H | U | R | R | I | C | A | N | E | H |
| W | C | T | S | L | M | N | O | P | T |
| M | Y | O | T | Y | P | H | O | O | N |
| O | C | R | O | H | C | T | P | Q | I |
| C | L | N | R | U | A | Y | R | S | N |
| F | O | A | M | R | N | P | T | U | G |
| P | N | D | X | R | E | H | Y | E | N |
| Z | E | O | A | I | O | U | N | Y | B |
Answer:
Six natural phenomenon in the given word diagram are: Thunderstorm, Typhoon, Cyclone, Tornado, Hurricane and Lightning.
| G | C | H | T | H | T | E | N | M | R |
| R | C | Y | H | O | O | N | C | Z | P |
| V | L | O | U | E | R | O | E | R | T |
| A | N | C | N | A | N | N | L | C | L |
| H | T | H | D | B | A | D | A | P | I |
| L | U | N | E | K | D | C | Y | D | G |
| H | U | R | R | I | C | A | N | E | H |
| W | C | T | S | L | M | N | O | P | T |
| M | Y | O | T | Y | P | H | O | O | N |
| O | C | R | O | H | C | T | P | Q | I |
| C | L | N | R | U | A | Y | R | S | N |
| F | O | A | M | R | N | P | T | U | G |
| P | N | D | X | R | E | H | Y | E | N |
| Z | E | O | A | I | O | U | N | Y | B |
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