MCQ Questions for Class 6 Science: Ch 15 Air around Us

MCQ Questions for Class 6 Science: Ch 15 Air around Us

1. Mountaineers carry oxygen cylinders with them because
(a) oxygen supports combustion.
(b) oxygen is less at higher altitudes.
(c) more oxygen is needed to cook food.
(d) oxygen does not support combustion.
► (b) oxygen is less at higher altitudes.

2. Which of the following plays a very important role in the oxygen cycle?
(a) Birds
(b) Animals
(c) Plants
(d) Soil
► (c) Plants

3. The balance between carbon dioxide and oxygen is maintained by
(a) Evaporation and photosynthesis
(b) Transpiration and respiration
(c) Photosynthesis and respiration
(d) Hydrogenation and combustion
► (c) Photosynthesis and respiration

4. The layer of air around the earth surface is called
(a) Hydrosphere
(b) Lithosphere
(c) Atmosphere
(d) Stratosphere
► (c) Atmosphere

5. The active part of air is
(a) Carbon dioxide
(b) Oxygen
(c) Rare gases
(d) Carbon monoxide
► (b) Oxygen

6. The components of air which are harmful to living beings are
(a) Nitrogen and carbon dioxide
(b) Dust and water vapour
(c) Smoke and water vapour
(d) Dust and smoke
► (d) Dust and smoke

7. Which of the following processes need oxygen?
(a) Combustion
(b) Respiration
(c) Oxidation
(d) All of the above
► (d) All of the above

8. Atmospheric pressure _____________ with height.
(a) Increase
(b) Decrease
(c) Depends upon season
(d) Remain same
► (b) Decrease

9. Finer hair inside the nose
(a) Filter the microbes
(b) Prevent the water vapour
(c) Prevent the carbon dioxide gas
(d) Filter the dust particle
► (d) Filter the dust particle

10. The presence of air around can be proved by
(a) Seeing it
(b) Feeling it when moves
(c) Smelling it
(d) Its colour
► (b) Feeling it when moves

11. Density of air ____________ with height.
(a) Increase
(b) Remain same
(c) Decrease
(d) First increase than decrease
► (c) Decrease

12. Which of the following is combustible?
(a) Oxygen
(b) Carbon dioxide
(c) Hydrogen
(d) All of these
► (c) Hydrogen

13. The percentage of nitrogen in air is
(a) 21%
(b) 0.1%
(c) 54%
(d) 78%
► (d) 78%

14. The nitrogen content in air is
(a) 88%
(b) 21%
(c) 78%
(d) 68%
► (c) 78%

15. A gas used for welding purpose is
(a) Neon
(b) Nitrogen
(c) Carbon dioxide
(d) None of these
► (c) Carbon dioxide

16. Which of the following gas is found in largest quantity in air?
(a) Nitrogen
(b) Carbon dioxide
(c) Argon
(d) Oxygen
► (a) Nitrogen

17. When we heat water, we find bubbles coming from it. This shows that
(a) water contains air.
(b) air contains water.
(c) water itself converts into bubbles.
(d) water contains dissolved minerals.
► (a) water contains air.

18. Mountaineers carry oxygen ______________ with them, while climbing mountains.
(a) Filer
(b) Cylinder
(c) Mask
(d) Bag
► (b) Cylinder

19. Which of the following can show the direction of the wind?
(a) An anemometer
(b) A wind mill
(c) A windvane
(d) A barometer
► (c) A windvane

20. Name the object which is inflated by air
(a) Balloons
(b) Table
(c) Buckets
(d) Chair
► (a) Balloons

21. All animals including human exhale
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Water vapour
► (c) Carbon dioxide

22. Which of the following statements is true regarding the earth's atmosphere?
(a) It gets denser with an increase in the altitude.
(b) It gets thinner with an increase in the altitude.
(c) It remains the same.
(d) It contains no solid particles.
► (b) It gets thinner with an increase in the altitude.

23. Moisture in air is called
(a) Atmosphere
(b) Humidity
(c) Water vapour
(d) Respiration
► (b) Humidity

24. Air is a __________ of some gases.
(a) Suspension
(b) Solution
(c) Compound
(d) Mixture
► (d) Mixture

25. Which of the following statements is true regarding the properties of air?
(a) Air is a good conductor of electricity.
(b) Air is a good conductor of heat.
(c) Air is translucent in nature.
(d) The composition of air varies from place to place.
► (d) The composition of air varies from place to place.

26. In which of the following place quality of air is best?
(a) Industrial area
(b) Busy road crossing
(c) Busy market place
(d) Park
► (d) Park

27. The nose and mouth of traffic police at crossing is covered with
(a) Mask
(b) Handkerchief
(c) Nets
(d) Towel
► (a) Mask

28. The humidity of a place
(a) lies between 10% - 20%.
(b) is always more than 50%.
(c) is always less than 80%.
(d) varies from time to time.
► (d) varies from time to time.
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