# Important Questions Test: Air Around Us

## 20 Questions MCQ Test NCERT Textbooks (Class 6 to Class 12) | Important Questions Test: Air Around Us

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Attempt Important Questions Test: Air Around Us | 20 questions in 20 minutes | Mock test for UPSC preparation | Free important questions MCQ to study NCERT Textbooks (Class 6 to Class 12) for UPSC Exam | Download free PDF with solutions
QUESTION: 1

### Which of these applies to nitrogen?

Solution:

Nitrogen gas comprises 78% of atmosphere. It does not help in respiration, photosynthesis and burning.

QUESTION: 2

### Moisture in air is called

Solution:

The quantity of water vapour present in air is called as humidity.

QUESTION: 3

### In which of the following place quality of air is best?

Solution:

Quality of air is best in park in comparison to industrial area, busy road crossing and busy market place.

QUESTION: 4

This is used as a fuel in rockets for combustion of fuels

Solution:

Hydrogen gas is used as fuel in rockets for combustion of fuels due to high calorific value.

QUESTION: 5

Finer hair inside the nose

Solution:

Finer hairs inside the nose filter the dust particle while inhaling the air.

QUESTION: 6

Winnowing is used to separate

Solution:

Winnowing is used to separate grains from husk due to difference in their density.

QUESTION: 7

The layer of air around the earth surface is called

Solution:

The layer of air around the earth surface is called atmosphere.

QUESTION: 8

Name the object which is inflated by air

Solution:

Balloons is inflated by air due to pressure of air.

QUESTION: 9

Density of air ____________ with height.

Solution:

Density of air decrease with height as we move upwards.

QUESTION: 10

Gases and fine dust particle together make the

Solution:

Gases and dust particle together make the smoke. Smoke starts from burning substances.

QUESTION: 11

Oxygen is used in hospitals for

Solution:

In hospital oxygen gas is used for artificial respiration for patient having respiratory problem.

QUESTION: 12

Atmospheric pressure _____________ with height.

Solution:

Atmospheric pressure decrease with height due to decrease in density of air.

QUESTION: 13

An empty glass is in fact

Solution:

There are many more water molecules in a glass of water than nitrogen and oxygen molecules in an empty glass. About 1000 times as many. Molecules in a gas are about 10 times as much distance from each other than molecules in a liquid or solid.

QUESTION: 14

The balance between carbon dioxide and oxygen is maintained by

Solution:

The balance between carbon dioxide and oxygen is maintained by photosynthesis and respiration in which carbon dioxide and oxygen is used and oxygen and carbon dioxide is produced respectively.

QUESTION: 15

All animals including human exhale

Solution:

All animals including human exhale carbon dioxide gas and inhale oxygen gas.

QUESTION: 16

Which of the following gas is found in largest quantity in air?

Solution:

Nitrogen gas is found in largest quantity in air followed by oxygen gas.

QUESTION: 17

During rain, soil animals comes out from their burrows for

Solution:

During rain, soil animals come out from their burrows for respiration as their burrow is filled by water.

QUESTION: 18

Animals living in water have ____________ for respiration.

Solution:

Animals living in water have gills for respiration which intake oxygen gas dissolved in water.

QUESTION: 19

In which of the following air is not used?

Solution:

Air is not required for boiling water but required for inflating tyres, filling balloon and winnowing.

QUESTION: 20

The components of air which are harmful to living beings are

Solution:

The components of air which are harmful to living beings are dust and smoke that cause pollution.

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