Class 6 Science Chapter 11 MCQ

Bubbles of air came out from the bottle and some water entered into the bottle, when it was tilted.

Here, all these statements are correct. Hence, your answer will be option [D].

As we go up above the sea level, the atmospheric pressure goes on decreasing and the amount of oxygen also decreases at higher altitude. This is why, mountaineers carry oxygen, cylinders with them.

The presence of water vapour in air is important for the working of water cycle in nature (This is because it is water vapour present in air which rises high in the sky along with hot air, gets cooled, condenses to form clouds and then brings rain on the earth).

Air also helps in the flight of birds and aeroplanes.

We should never breathe in air or inhale air through our mouth because if we breathe through our mouth then dust particles present in air may enter our respiratory system (lungs etc.) and damage our health.

Here, all these statements are correct. Hence, your answer will be option [D].

The major part of air which support burning candle, is oxygen not nitrogen.

Dust and smoke present in air are harmful to living beings. Note: Breathing in air containing smoke and dust may enter our respiratory system (lungs, etc.) and damage our health.

Nitrogen is present in the largest amount in the atmosphere. It occupies 78.09% of atmosphere.

Here, all these statements are correct. Hence, your answer will be option [D].

Here, all these statements are correct. Hence, your answer will be option [D].

Here, are all the statements are correct. Hence, your answer will be option [D].

The bubbles contain air because soil absorbs some amount of air. The air is present in the spaces between the soil particles.

Nitrogen and oxygen gases taken together make up about 99% of air. Thus, air is a mixture of many gases. Generally, air is mainly a mixture of nitrogen and oxygen gases with small amounts of carbon dioxide gas, water vapour and other gases. And some dust particles may also be present in air. Air contains 78 % nitrogen, 21% oxygen and remaining 1% contains carbon di oxide, water vapor, dust particles and other gases.

The components of air which is utilized by the plants in respiration is oxygen. Thus, animal depends on plants for getting oxygen gas for reparation or breathing and plants depend on animals for getting carbon dioxide gas for photosynthesis only in day time or presence of sunlight, but respiration occurs always (day-night) in plants.

Air is a mixture of many gases. The major components of air is nitrogen gas. Almost four-fifths of air is nitrogen gas. The second major component of air is oxygen gas. About one-fifth of air is oxygen gas. In addition to nitrogen and oxygen gases, air also contains some small amounts of carbon dioxide gas water vapour and other gases (such as argon and helium etc.). The air may also contain some dust particles also.

All the living things need nitrogen compounds for their growth. Plants use nitrogen gas of the air to make proteins. These proteins are used by the plants for their own growth as well as for the growth of human beings and other animals. Thus, nitrogen is needed by plants to make proteins.

Air is a mixture of many gases. Generally, air is mainly a mixture of nitrogen and oxygen gases with small amounts of carbon dioxide gas, water vapour and other gases. And some dust particles may also be present in air. Air contains 78 % nitrogen, 21% oxygen and remaining 1% contains carbon di oxide, water vapor, dust particles and other gases.

The composition of air is not always exactly the same. The composition of air changes slightly from place to place and the season to season. For example, the air over in industrial cities usually has a higher amount of carbon dioxide in it, than the air over open spaces. The air in coastal areas may have more water vapour than inland areas. The air also contains more water vapour in rainy season. Similarly, the amount of dust in the air is more in windy places than other places.

The plants get fertilizers, carbon dioxide, and irrigation from humans, except an oxygen. Thus, animal depends on plants for getting oxygen gas and plants depend on animals for getting carbon dioxide gas.

Carbon monoxide is produced by the incomplete combustion of carbon-containing fuels, such as gas (domestic or bottled), coal, oil, coke and wood. Gas stoves, fires, heating boilers, gas-powered water heaters, paraffin heaters, and solid fuel-powered water heaters are all potential sources of carbon monoxide. Air do not contain these types of gases. Air is a mixture of many gases. Generally, air is mainly a mixture of nitrogen and oxygen gases with small amounts of carbon dioxide gas, water vapour and other gases. And some dust particles may also be present in air. Remember the composition of air is not always exactly the same.

We know that water does not enter the bottle when it is in an inverted position, as there was no space for air to escape. When the bottle was tilted, the air was able to come out in the form of bubbles, and water filled up the empty space that the air has occupied. This activity shows that air occupies space. It fills all the space in the bottle.

We get oxygen, fuel and food from plants, except carbon dioxide. Animal depends on plants for getting oxygen gas and plants depend on animals for getting carbon dioxide gas.

When the burning clothes of a person are covered with woolen blanket, then the supply of fresh air is cut off and hence the clothes stops burning or the fire gets extinguished. The three things which are essential to ignite any fire. As oxygen, heat, and fuel are frequently referred to as the “fire triangle.” The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished. Remember, wool is comparatively capable to trap much more air than any others fibres. And fire will be stop due to lack of oxygen.