Air

Q.

Briefly Describe The Central Idea Of The Poem Wind ?

Q.

What is the importance of oxygen for living beings?

Q.

We can survive for some time without air but we cannot survive even for a few minutes without food. State true or false. Correct if wrong statement.

1. True
2. False

Q.

State true or false.
Moving air has energy associated with it.

1. True

2. False

Q.

Which of the following is not a property of air?

1. Air has mass.
2. Air occupies space.
3. Air is colourless.
4. Air has taste and odour.

Q. Which gas makes up around 21% of our atmosphere?

1. Nitrogen
2. Hydrogen
3. Oxygen
4. Carbon dioxide

Q.

How do two gases get mixed?

Q. A balloon when inflated weighs more than when it is deflated. This proves that air has _______.

1. mass
2. volume
3. odour
4. taste

Q.

Explain the term background radiation.

Q.

The composition of air is always the same in every place

1. True
2. False

Q.

The component air which comprises more than the $\frac{3}{4}th$ composition of air is

1. Carbon-dioxide

2. Nitrogen

3. Argon

4. Oxygen

Q. Which one of the following is not a physical property?

1. Smell
2. Size
3. Shape
4. Flammability

Q.

Liquid air has a definite boiling point.

1. True

2. False

Q. The most abundant gas found in air is:

1. Oxygen
2. Sulphur
3. Nitrogen
4. Hydrogen

Q.

The blowing of wind is caused due to the pressure difference.

1. False

2. True

Q. The direction of the wind at a particular place can be shown by ___________.

1. weather vane
2. wind machine
3. weather forecast
4. weather predictor

Q.

Which of the following option shows the correct percentage composition of the component of air?

1. Nitrogen - 69.5 %

2. Oxygen - 20.9%

3. Carbon dioxide - 0.04%

4. Argon - 2%

Q.

Explain the factors that cause the wind to blow.

Q.

The energy associated with air is because:

1. of the fact that air is a mixture of gases

2. of the density of air

3. of the motion of the gaseous particles

4. air is transparent

Q.

0.03% of air: CO₂ : 78.08% of air : ___________

Q.

Air contains about 21% oxygen by ______

Q.

The composition of air is not constant everywhere.

1. True
2. False

Q.

Which of the following is true about properties of air?

1. Colourless

2. Odourless

3. Visible from eyes

4. Solid

Q.

In a room the light is not reaching directly even then it is illuminated. Why?

Q.

Tick the most appropriate answer

Air consist of

1. oxygen only

2. nitrogen only

3. ${\mathrm{CO}}_2$ only

4. all of these

Q.

24 (a) State whether the following statements are true or false.

Air consists of a single substance.

1. True
2. False

Q. The layer of air around the Earth is known as

Q. Which of the following is the most abundant gas in the Earth's atmosphere?

1. Hydrogen
2. Nitrogen
3. Oxygen
4. Argon

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. All of the above.

2. Oxygen is 1/5th the volume of air.

3. The ratio of oxygen and nitrogen in air is 1:4.

4. Oxygen is required for burning the candle.

Q.

Air is transparent because:

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

2. Some constituents of air absorb light rays that fall on them.

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

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