Class 7 Geography
Question 1: Define exosphere.
Answer: It is the uppermost layer of the atmosphere having very thin air.
Question 2: Define global warming.
Answer: General increase in earth’s temperature is called global warming.
Question 3: What are the components of the atmosphere?
Answer: Nitrogen, oxygen, carbon dioxide, helium, argon, other gases and dust.
Question 4: Define weather.
Answer: Hour to hour, day to day conditions of the atmosphere is called weather.
Question 5: What are the layers of the atmosphere?
Answer: Troposphere, stratosphere, mesosphere, thermosphere and exosphere.
Question 6: What is climate?
Answer: The average weather of a place over a longer period of time.
Question 7: What is insolation?
Answer: Insolation is the incoming solar energy intercepted by the earth.
Question 8: Define humidity.
Answer: Moisture in the air at any time.
Question 9: What are clouds?
Answer: Masses of water droplets are called cloud.
Question 1: What is the signifincance of oxygen for us?
Answer: Oxygen is the second most plentiful gas in the air. Most of the living beings need oxygen for respiration. Thus, oxygen is important for survival of life on earth.
Question 2: What is mesosphere?
Answer: It is the third layer of the atmosphere and it lies above the stratosphere. It extends upto a height of 80 km. The burning of meteorites on entering from space occurs in this layer.
Question 3: Write briefly about nitrogen gas.
Answer: It is the gas that is most abundant in the air. Nitrogen is an important component of protein. Plants cannot take up gaseous nitrogen. They need help of various agents of nitrogen fixation in order to utilize nitrogen.
Question 4: What is temperature?
Answer: It is the degree of hotness or coldness of the air. It changes between day and night and from season to season. Summers have a higher temperature than winters. It is measured using a thermometer.
Question 1: Describe the composition of the air.
Answer: The air that we breathe is a mixture of many gases like oxygen, nitrogen, carbon dioxide, argon etc. The majority of the atmosphere is made up of nitrogen (78%) and oxygen (21%). The other gases that are present in small quantities are:
Question 2: Describe the layers of the atmosphere.
Answer: Our atmosphere is divided into five layers which are:
Question 3: Write in detail about winds.
Answer: The movement of air from high pressure area to low pressure area is called wind. Winds can be gentle or very strong. Gentle winds blow away smoke or fine dust. An extremely strong wind is in the nature of a storm which can even uproot trees. A wind can be strong enough to make it difficult to walk against it. Broadly, winds can be divided into three types:
Question 4: Describe air pressure.
Answer: Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface.
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