Air Is Everywhere

Q. Why do the doctors advise to put strips of wet cloth on the forehead of a person having high fever?

Q. What is air pollution? Mention a few common causes of air pollution. [3 MARKS]

Q. Air pollution is caused only by humans.

1. True
2. False

Q.

Pollution causes change in environment.

Say True or False.

1. True

2. False

Q. Describe an experiment which shows that air is dissolved in water. Make a diagram depicting the process. [5 MARKS]

Q.

The amount of water vapour present in air same everywhere.

1. Air present in lump of cotton is replaced by water which occupies less space.

2. Air doesn't occupy space but water does.

Q. When a person is caught with fire, he or she is wrapped in a thick blanket so as to ___.

1. cut off the oxygen supply
2. cut off the nitrogen supply
3. keep the body cool
4. cut off the inert gases supply

Q.

Air is not present in ___ .

1. Buildings

2. Vacuum

3. Caves

4. Ocean

Q. An animal placed in an airtight jar and is kept in sunlight, as shown in the figure.

How can the animal be helped to survive for a long time?

1. By placing a green plant in it
2. By removing all the air through a vacuum pump
3. By placing a burning candle in it
4. By placing another mouse in it

Q. Read the two statements given below
(i) The compressed air in a tyre exerts a force enough to lift a heavy car.
(ii) In a syringe, the plunger compresses the liquid.
Find out the true statements.

1. Both the statements are true.
2. Statement (i) is false but statement (ii) is true.
3. Both the statements are false.
4. Statement (i) is true but statement (ii) is false.

Q. In the given figure, a burning candle is kept in the trough containing water. It is put off after some time when covered by an inverted gas jar.

What can be concluded from the above activity?

1. The ratio of oxygen and nitrogen in air is 1:4.
2. Oxygen is required for burning the candle.
3. All of the above.
4. Oxygen is 1/5th the volume of air.

Q.

Choose the odd one out.

1. Driving a car
2. Flying of kite
3. Rustling of leaves
4. Moving blades of a windmill

Q. Which among the following is gaseous form of water?

1. Steam
2. Snow
3. Ice
4. Hailstone

Q. Choose the correct pair of gases according to their percentage composition in the air.

1. Nitrogen
2. Oxygen
3. Argon
4. $78\%$
5. $20.9\%$
6. $0.9\%$

Q.

Air is not present in

1. Caves

2. Ocean

3. Vacuum

4. Buildings

Q. Water vapour condenses to form drops of water higher up in the atmosphere. Why is the atmosphere cooler higher up?

Q. When we heat water, we find bubbles coming from it. This shows that

1. water contains air.
2. air contains water
3. water itself converts into bubbles.
4. water contains dissolved minerals.

Q. During winter season, presence of dew drops on leaves is a common site in gardens. During the formation of these dew drops, water changes its state from ______ to ______.

1. gaseous, liquid
2. gaseous, solid
3. liquid, gaseous
4. liquid, solid

Q. In the passage, which word means 'lost all the air'?

1. Irriated
2. Pleaded
3. Deflated
4. Refused

Q.

Why do you think air is transparent?

1. Air allows almost all the light that falls on it to pass through.

2. Air traps all the light that falls on it.

3. Constituents of air absorb a significant amount of light rays that fall on them.

4. Air reflects all the light that falls on it.