NCERT Class 8 Science MCQ | Chapter 6: Pressure, Winds, Storms, and Cyclones
1. What is pressure?
(A) Force per unit area
(B) Area per unit force
(C) Mass per unit volume
(D) Force multiplied by area
Answer: (A) Force per unit area
2. What is the SI unit of pressure?
(A) Newton
(B) Joule
(C) Pascal
(D) Watt
Answer: (C) Pascal
3. Why do broad bag straps feel more comfortable than narrow straps when carrying the same weight?
(A) Broad straps reduce the weight of the bag
(B) Broad straps spread the force over a larger area
(C) Broad straps increase the force on the shoulders
(D) Narrow straps have no pressure
Answer: (B) Broad straps spread the force over a larger area
4. Which statement about pressure is correct?
(A) Pressure decreases when the same force acts on a smaller area
(B) Pressure increases when the same force acts on a smaller area
(C) Pressure is independent of area
(D) Pressure is always equal to force
Answer: (B) Pressure increases when the same force acts on a smaller area
5. Why is it easier to drive a nail using its pointed end?
(A) The pointed end has a larger area
(B) The pointed end produces less pressure
(C) The pointed end has a smaller area, producing greater pressure
(D) The pointed end has no force acting on it
Answer: (C) The pointed end has a smaller area, producing greater pressure
6. A force of 100 N acts on an area of 2 m². What pressure is produced?
(A) 20 N/m²
(B) 50 N/m²
(C) 100 N/m²
(D) 200 N/m²
Answer: (B) 50 N/m²
7. What happens to the pressure exerted by a liquid when the height of the liquid column increases?
(A) It decreases
(B) It remains unchanged
(C) It increases
(D) It becomes zero
Answer: (C) It increases
8. Why are overhead water tanks placed at a height?
(A) To reduce the pressure of water
(B) To increase the pressure of water in taps
(C) To make the water colder
(D) To reduce the amount of water stored
Answer: (B) To increase the pressure of water in taps
9. Liquids exert pressure:
(A) Only at the bottom of a container
(B) Only on the sides of a container
(C) In all directions
(D) Only upwards
Answer: (C) In all directions
10. Why is the base of a dam made broader than its top?
(A) Water pressure is greater near the bottom
(B) Water pressure is zero near the bottom
(C) The top of the dam contains more water
(D) The base does not experience water pressure
Answer: (A) Water pressure is greater near the bottom
11. What is the atmosphere?
(A) The layer of water surrounding Earth
(B) The envelope of air surrounding Earth
(C) The solid layer below Earth’s surface
(D) The layer of clouds only
Answer: (B) The envelope of air surrounding Earth
12. What is atmospheric pressure?
(A) Pressure exerted only by clouds
(B) Pressure exerted by the air around us
(C) Pressure exerted only by water vapour
(D) Pressure exerted by Earth’s surface
Answer: (B) Pressure exerted by the air around us
13. Why does a rubber sucker stick to a smooth surface?
(A) Air pressure inside the sucker becomes greater than outside
(B) Air pressure outside the sucker is greater than inside
(C) Gravity stops acting on the sucker
(D) The surface becomes magnetic
Answer: (B) Air pressure outside the sucker is greater than inside
14. What happens when air is blown into a balloon?
(A) The balloon contracts because air exerts no pressure
(B) The balloon expands because the air inside exerts pressure on its walls
(C) The balloon becomes heavier only
(D) The air pressure outside becomes zero
Answer: (B) The balloon expands because the air inside exerts pressure on its walls
15. In which direction does air naturally move?
(A) From low pressure to high pressure
(B) From high pressure to low pressure
(C) Only from land to sea
(D) Only from sea to land
Answer: (B) From high pressure to low pressure
16. Why does air move from one region to another?
(A) Because of differences in air pressure
(B) Because air has no mass
(C) Because all regions have equal pressure
(D) Because gravity stops acting on air
Answer: (A) Because of differences in air pressure
17. During the daytime, why does sea breeze blow from the sea towards the land?
(A) Land heats faster than water, causing warm air over land to rise
(B) Water heats faster than land
(C) Air over the sea always has lower pressure
(D) The sea pulls the air towards itself
Answer: (A) Land heats faster than water, causing warm air over land to rise
18. What happens to air pressure when air is heated?
(A) Warm air becomes lighter and rises, creating a low-pressure area
(B) Warm air becomes heavier and sinks
(C) Warm air always creates a high-pressure area
(D) Heating has no effect on air pressure
Answer: (A) Warm air becomes lighter and rises, creating a low-pressure area
19. What happens when air is blown rapidly between two balloons?
(A) The balloons move away from each other
(B) The balloons move towards each other
(C) The balloons stop moving
(D) The balloons become inflated
Answer: (B) The balloons move towards each other
20. Why can high-speed winds blow away weak roofs?
(A) High-speed winds create lower pressure above the roof
(B) High-speed winds increase pressure above the roof
(C) Gravity disappears during strong winds
(D) The roof becomes heavier
Answer: (A) High-speed winds create lower pressure above the roof
21. What causes lightning during a thunderstorm?
(A) The collision of clouds with mountains
(B) A sudden flow of electric charges after the insulating property of air breaks down
(C) The heating of rainwater
(D) The movement of wind alone
Answer: (B) A sudden flow of electric charges after the insulating property of air breaks down
22. What is thunder?
(A) A bright flash produced by clouds
(B) A loud sound produced when lightning rapidly heats and expands the surrounding air
(C) The movement of water droplets
(D) A strong wind near the ground
Answer: (B) A loud sound produced when lightning rapidly heats and expands the surrounding air
23. What is the safest action during lightning?
(A) Stand under a tall tree
(B) Stay in an open field while standing upright
(C) Take shelter in a building or vehicle and stay away from tall objects
(D) Hold an umbrella with a metallic rod
Answer: (C) Take shelter in a building or vehicle and stay away from tall objects
24. How does a cyclone form over warm ocean water?
(A) Warm moist air rises, creating a low-pressure area, and surrounding air rushes in and begins to rise and rotate
(B) Cold air sinks and completely stops wind movement
(C) Ocean water freezes and produces strong winds
(D) High pressure develops at the centre and stops air movement
Answer: (A) Warm moist air rises, creating a low-pressure area, and surrounding air rushes in and begins to rise and rotate
25. Which statement about the eye of a cyclone is correct?
(A) It is the region of highest pressure with the strongest winds
(B) It is the centre of lowest pressure where winds are relatively calm
(C) It is always outside the cyclone
(D) It receives no rainfall anywhere around it
Answer: (B) It is the centre of lowest pressure where winds are relatively calm
NCERT Class 8 Science MCQ | Chapter 6: Pressure, Winds, Storms, and Cyclones
Assertion–Reason Questions
Directions: Choose the correct option:
(A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(C) Assertion is true, but Reason is false.
(D) Assertion is false, but Reason is true.
1. Assertion: Broad straps of a school bag are more comfortable than narrow straps when carrying the same weight.
Reason: Broad straps increase the area over which the force acts and therefore reduce pressure.
Answer: (A)
2. Assertion: The pressure exerted by a liquid increases with the height of its liquid column.
Reason: A higher liquid column exerts greater pressure at the bottom of the container.
Answer: (A)
3. Assertion: Air moves from a region of high pressure to a region of low pressure.
Reason: Differences in air pressure cause air to move from higher-pressure regions towards lower-pressure regions.
Answer: (A)
4. Assertion: High-speed winds can cause roofs of houses to be blown away.
Reason: High-speed winds are accompanied by reduced air pressure above the roof, creating a pressure difference between the inside and outside of the house.
Answer: (A)
5. Assertion: The eye of a cyclone is a region of relatively calm winds.
Reason: The eye is located at the centre of the cyclone where the pressure is lowest, while the surrounding region experiences strong winds and heavy rainfall.
Answer: (B)
