Chapter-4: AIR TEST

Identify which of the following two gases make up the bulk of the atmosphere.

• Nitrogen and Oxygen

• Oxygen and Carbon dioxide

• Argon and hydrogen

• Hydrogen and Helium

Identify the way through which plants recieve nitrogen.

• Plants take nitrogen directly from the air.

• Plants take nitrogen through water.

• Plants take nitrogen through bacteria that live in the roots of plants.

• None of the above

Green plants produce ________ during photosynthesis.

Define Global warming. (Short answer)

Answer explanation

Carbon dioxide released in the atmosphere creates a green house effect by trapping the heat radiated from the earth. It is therefore called greenhouse gas. When its level increases due to factory smoke, car fumes, the heat retained increases the temperature of the earth and this is called global warming

Identify the average height of troposphere.

• 8 Km

• 10 Km

• 50 Km

• 13 Km

Recognize the layer of gas Stratosphere contains.

• Helium

• Ozone

• Carbon dioxide

• Oxygen

Identify the layer of atmosphere in which meteorites burn.

• Troposphere

• Stratosphere

• Mesosphere

• Thermosphere

Describe weather and climate. (Short answer)

Answer explanation

Weather is day to day and hour to hour condition of the atmosphere. It can change dramatically from day to day. However, the average weather condition of a place for a longer period of time represents climate of a place.

Explain the cause of differences in temperature over the earth. (Short answer)

Answer explanation

Insolation i.e. incoming solar radiation is the main cause of temperature distribution. The amount of insolation decreases from the equator towards the poles, therefore temperature decreases in the same manner.

Explain the movement of air by analyzing the image and also tell the reason behind it. (Short answer)

Answer explanation

Air moves from high pressure areas to low pressure areas. The reason is when the temperature rises, air gets heated, warm air rises and creates a low pressure. In areas of low temperature air is cold which heavy, dense and thus it sinks and creates a high pressure area. Hence air moves from high pressure to low pressure.