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 1: (d) On the ceiling
The air above the fire gets heated in the event of a fire, so fire detectors are set on the ceiling.
Question 2: Four schematic diagrams are shown in Figure 8.1 to depict the direction of the sea breeze. Which of them gives the correct direction?
Solution 2: (c)
Air rises over land during the summer as land gets heated. This allows the colder air to blow into the ground from the sea. That air is called the wind of the sea.
Question 3: Figure 8.2 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 the rise in the level of the drink?
(a) The 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) The blowing of air warms up the air inside the straw.
(d) The blowing of air increases the pressure on the surface of the soft drink in the bottle.
Solution 3: (a) Blowing of air decreases pressure over the opening of the straw.
The decreased pressure on the opening of the straw increases the amount of soft drinks.
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 4: (d) (iv)
In the case of storm is accompanied by lightening any person can take shelter in the bus.
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 5: (b) Puri
Puri is most likely to be affected by cyclone as it lies near the coastal region.
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 6: (b) get pushed outside the room.
The air pressure rises if a strong wind blows down the hallway, and the curtain is pulled outside the room.
Very Short Answer Questions................
Question 7: Why is Chandigarh unlikely to be affected by a cyclone?
Solution 7: Chandigarh is very far from the sea, which is why a cyclone is unlikely to impact it.
Question 8: Name the ocean which is mainly responsible to bring rain-bearing monsoon winds to Kerala coast in June every year?
Solution 8: Indian Ocean is 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 9:
(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.
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 coastline of India is not vulnerable to cyclones.
(iv) Warm air is lighter than cool air.
Solution 10:
(i) False- If the wind blows from the ground to the ocean, so it's time for night, so the sea cools off more slowly than the earth at night. So, the cold breeze sails into the ocean from the shore.
(ii) False – A cyclone is formed by a very low-pressure system, with very high-speed winds revolving around it.
(iii) False- The entire coastline of India, particularly the east coast, is vulnerable to cyclones.
(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 11: B's exhaust fan can essentially remove the hot air as the air rises and its fan is higher than A's in height.
Question 12: Why is it advisable not to shut all the doors and windows during a storm?
Solution 12: It is advisable not to shut all the doors and windows during storm because of the low pressure produced by heavy wind, to protect the roof from being swept away.
Question 13: A flat in Mumbai with a balcony facing the sea has some clothes hung on a clothesline in the balcony. Towards which direction the clothes will be blown in the afternoon? Explain.
Solution 13: That the wind of the sea blowing towards the clothes of the ground would blow towards the house.
Question 14: Figure 8.3 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 14: The shore is on the B line, when the wind blows from the sea to the ground.
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 15: A flag mounted on a flag post near the sea coast flutters in the direction of sea. At midnight, because of the land breeze.
Short Answer Questions............
Question 16: Match Column I with Column II. There can be more than one match.
Solution 16:
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 17: Owing to the low temperature, the air inside the container contracts, so the bottle collapses because of the outer pressure.
Question 18: When strong/high-speed wind blows, an umbrella held upright at times gets upturned. Explain the reason.
Solution 18: Umbrella upturns generate low pressure due to the high-speed water flowing through the umbrella.
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 19: (i) Put heavy stones on it.
(ii) Screw it tight.
Long Answer Questions...............
Question 20. Describe an activity to demonstrate that warm air is lighter than cool air.
Solution 20: Take two bags of paper or empty cups of paper that are the same size. From both ends of a metal or wooden handle, hang the two bags in an inverted way. Tie the center of the stick with a bit of yarn. Like a balance, keep the stick by the thread (Fig). As seen in the figure, placed a burning candle below one of the bags. It raises the bag above the candle as the warm air rises.
Question 21: The picture in Figure 8.4 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 21: Heating and air cooling are a common occurrence in the coastal regions of an island near the equator. Compared to the water in the bay, the ground heats up rapidly during the daytime. The air above the earth heats up and rises and is replaced by the cold sea air that gives rise to the sea breeze. This sea breeze makes the trees bend in the direction of the property.
Question 22: Identify the names of six natural phenomena from the following word diagram given as Figure 8.5.
Solution 22:
