Important Questions Test: Air Around Us

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

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

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

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

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

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

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

Balloons is inflated by air due to pressure of air.

Density of air decrease with height as we move upwards.

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

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

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

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.

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.

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

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

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

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

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

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