Important Notes : Atmosphere

Atmosphere

• The atmosphere is a vast expanse of air surrounding the earth’s surface. It Envelops the earth and makes life possible on the planet 
• It is intact to the earth’s surface with the help of the Earth’s Gravitational Force 
• The atmosphere maintains the average temperature on the earth 
• It protects the earth from the harmful UV radiations
• Life exists on earth because of atmosphere 

DIVISION –

 The atmosphere may be broadly divided into Homosphere and Heterosphere

• Homosphere extends Upto 90 km and is Uniform in composition 
• Heterosphere is above 90 km. It is Non- uniform in composition 

There are various gasses on the earth’s atmosphere which serves various purposes 

COMPOSITION OF THE ATMOSPHERE-

· Nitrogen regulates combustion, Generates protein in plants and is spread upto a height 120 km

· Oxygen is the mandatory gas for breathing, combustion with varying concentration at 16 km, 64 km, 120 km

· Carbon dioxide is a Heavy gas with concentration upto 32 km

· Hydrogen with a percentage of approximately 0.01% extends mostly upto 1100km

· Ozone concentrated in 20-25km protects the earth from UV radiations 
LAYERS OF THE ATMOSPHERE-

Troposphere-

• The zone of Earth's atmosphere immediately above its surface up to a height of about 16 kms above the equator and 8 kms over the poles 
• Density of The Earth's atmosphere is highest in the troposphere 

Stratosphere

• The stratosphere is where the very important ozone layer exist.
• The ozone layer helps protect us from ultraviolet radiation (UV) from the sun.
• cold, heavy air is at the bottom and warm, light air is at the top

Mesosphere

• lies between the thermosphere and the stratosphere.
•  “Meso” means middle
• Temperature decreases with height throughout the mesosphere. 
• The coldest temperatures in Earth's atmosphere, about -90° C (-130° F)

Thermosphere

• “Thermo” means heat
•  The temperature in this layer can reach up to 4,500 degrees Fahrenheit.

 Exosphere 

the outermost region of a planet's atmosphere.

Q. The atmospheric layer closest to the ground is?
A. Mesosphere

B. Troposphere

C. Thermosphere

D. Stratosphere

Ans-b 

Q. Nitrogen constitutes nearly of the earth’s atmosphere.

A. 79

B. 21

C. 57

D. 42

Ans-a

Q. Which of the following is not a constituent of the atmosphere?

A. Oxygen 

B. Aluminium

C. Nitrogen 

D. Carbon Dioxide

Ans-b 

Q. . Which of the following is necessary for a substance to burn or combustion?

A. Light 

B. Gasoline 

C. Hydrogen 

D. Oxygen

Ans-d

Q. Which layer has the ozone layer in it?

A. Mesosphere

B. Troposphere

C. Thermosphere

D. Stratosphere

Ans-d

Q. The coldest layer in the atmosphere is?

A. Mesosphere

B. Troposphere

C. Thermosphere

D. Stratosphere

Ans-a

Q. Which atmospheric layer has most of the clouds ?

A. Mesosphere

B. Troposphere

C. Thermosphere

D. Stratosphere

Ans-b