The Atmosphere

Total Questions: 23

1. The atmosphere is a mixture of several gases. Near the earth surface it contains mainly: [R.A.S/R.T.S. (Pre) 1997]

Correct Answer: (a) Nitrogen and oxygen
Solution:The atmosphere is a mixture of different gases, of which 99% are mainly Nitrogen (78.084%) and Oxygen (20.947%). Remaining approximately 1% are Argon, Carbon dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide, Ozone, Krypton, Xenon, etc.

Heavy gases are found at the bottom of atmosphere and light gases are found at the top. Carbon dioxide is found up to 20 km above Earth, Oxygen and nitrogen up to 100 km, Hydrogen up to 125 km and except Ozone other gases are found at much higher elevation

2. Which gas has a maximum percentage in the atmosphere? [U.P.P.C.S. (Pre) 1993]

Correct Answer: (b) Nitrogen
Solution:The atmosphere is a mixture of different gases, of which 99% are mainly Nitrogen (78.084%) and Oxygen (20.947%). Remaining approximately 1% are Argon, Carbon dioxide, Neon, Helium, Methane, Hydrogen, Nitrous Oxide, Ozone, Krypton, Xenon, etc.

Heavy gases are found at the bottom of atmosphere and light gases are found at the top. Carbon dioxide is found up to 20 km above Earth, Oxygen and nitrogen up to 100 km, Hydrogen up to 125 km and except Ozone other gases are found at much higher elevation

3. Which one of the following is the permanent gas in the atmosphere? [U.P. P.C.S. (Mains) 2017]

Correct Answer: (c) Nitrogen
Solution:Permanent gases in the atmosphere are those gases which quantity does not change from day to day. These gas primarily contain nitrogen, oxygen and argon. Except these three gases, the quantity of CO, Ozone and Neon keep on changing according to the circumstances.

4. The correct sequence of different layers of the atmosphere from the surface of the Earth upwards is: [I.A.S. (Pre) 1998]

Correct Answer: (c) Troposphere, Stratosphere, Mesosphere, lonosphere
Solution:On the basis of temperature and air pressure atmosphere is divided into five layers starting from the earth's surface which are as follows:

Troposphere- (15 km from the surface of the earth)

Stratosphere (15-50 km) Mesosphere (50-80 km)

Ionosphere (80-640 km)

Exosphere (above more than 640 km)

The thermosphere is located above the mesosphere and below the exosphere, and its lowest part contains Inosphere.

So option (c) is correct.

5. In the vertical structure of the atmosphere, which one is the lowest layer? [U.P. R.O./A.R.O. (Re Exam) (Pre) 2016]

Correct Answer: (c) Troposphere
Solution:The troposphere is the lowest layer and its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator.It is thickest at the equator because heat is transported to great heights by strong convection currents and much thinner at the North and South Poles.

Approximately 75 and 80 percent of the mass of the entire atmosphere is contained in the troposphere. Most of the water vapour in the atmosphere, along with dust and ash particles, are found in the troposphere that's why most of Earth's clouds are located in this layer. Temperatures in the troposphere decrease with altitude.

Tropopause: The zone separating the troposphere from the stratosphere is known as the tropopause. At the tropopause, the temperature of the air is about minus 80°C over the equator and about minus 45°C over the poles.

6. Which of the following statements is true about troposphere? [68ᵗʰ B.P.S.C. (Pre) 2022]

Correct Answer: (a) Its average height is 13 km.
Solution:In the Vertical structure of the atmosphere, Troposphere is the lowermost layer. Its average elevation is about 12 kms. All seasonal phenomena like rain, fog, hail, etc. occur on this surface.

7. The four layers of the atmosphere are - [U.P.P.C.S. (Mains) 2005]

1. Ionosphere

2. Mesosphere

3. Stratosphere

4. Troposphere

Their correct ascending order in terms of height is Code:

Correct Answer: (c) 4,3,2,1
Solution:In the Vertical structure of the atmosphere, Troposphere is the lowermost layer. Its average elevation is about 12 kms. All seasonal phenomena like rain, fog, hail, etc. occur on this surface.

8. Arrange the following atmospheric zones in terms of the distance from the earth's surface in increasing order and select the correct answer from the codes given below: [U.P.P.C.S. (Pre) (Re-Exam) 2015]

1. Thermosphere

2. Troposphere

3. Stratosphere

4. Mesosphere

Correct Answer: (d) 2,3,4,1
Solution:In the Vertical structure of the atmosphere, Troposphere is the lowermost layer. Its average elevation is about 12 kms. All seasonal phenomena like rain, fog, hail, etc. occur on this surface.

9. Most weather activity occurs in which atmospheric layer: [R.A.S./R.T.S. (Pre) 1999]

Correct Answer: (c) Troposphere
Solution:Almost all the weather phenomena like rainfall, fog and hailstorm, etc. occur in the troposphere. The temperature in this layer decreases at the rate of 6.5°C for every 1000 meter (1 km) height. This is the most important layer for all biological activity.

10. Which of the following atmospheric layers is known for all changes in climate and weather? [M.P.P.C.S. (Pre) 2023]

Correct Answer: (d) Troposphere
Solution:Almost all the weather phenomena like rainfall, fog and hailstorm, etc. occur in the troposphere. The temperature in this layer decreases at the rate of 6.5°C for every 1000 meter (1 km) height. This is the most important layer for all biological activity.