Question 1

Consider the following statements regarding the vertical distribution and composition of the atmosphere:
1. Approximately 99 per cent of the total mass of the atmosphere is confined to a height of 32 km from the earth’s surface.
2. Oxygen becomes almost negligible in quantity at a height of 90 km, while carbon dioxide and water vapour are found up to 120 km.
3. Ozone, which acts as a filter for ultra-violet rays, is primarily found in a layer between 10 and 50 km above the earth’s surface.
How many of the above statements are correct?

Accepted Answer

Only two. Statement 1 is correct. A significant majority, 99 per cent, of the atmosphere's total mass is concentrated within the first 32 km from the Earth's surface. Statement 2 is incorrect due to a numerical swap. Oxygen becomes almost negligible at a height of 120 km, not 90 km. Conversely, carbon dioxide and water vapour are primarily found only up to 90 km from the surface, not 120 km. Statement 3 is correct. The ozone layer, which filters harmful ultra-violet radiation, is located in the atmospheric stratum between 10 and 50 km above the Earth's surface. As statements 1 and 3 are correct, the correct option is 'Only two'.

Question 2

Consider the following statements regarding the properties of atmospheric components:
1. Water vapour concentration decreases from the poles towards the equator and contributes to atmospheric stability and instability.
2. Carbon dioxide is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation, making it a key gas for the greenhouse effect.
3. The highest concentration of dust particles is found in equatorial and polar regions compared to subtropical and temperate regions.
How many of the above statements are correct?

Accepted Answer

Only one. Statement 1 is incorrect. This statement reverses the actual spatial distribution. Water vapour concentration is highest in the warm, wet tropics and decreases from the equator towards the poles, not the other way around. Statement 2 is correct. Carbon dioxide's role in the greenhouse effect stems from its property of being transparent to incoming shortwave solar radiation but opaque to outgoing longwave terrestrial radiation, which it absorbs and re-radiates. Statement 3 is incorrect. This is a spatial swap. Due to dry winds, the higher concentration of dust particles is found in subtropical and temperate regions, not in the equatorial and polar regions. Therefore, only one statement is correct.

Question 3

Consider the following two statements:
Statement I: Carbon dioxide is a meteorologically very important gas and is largely responsible for the greenhouse effect.
Statement II: Carbon dioxide is transparent to the incoming solar radiation but is opaque to the outgoing terrestrial radiation, absorbing a part of it.
Which one of the following is correct in respect of the above statements?

Accepted Answer

Both Statement I and Statement II are correct and Statement II is the correct explanation for Statement I.. Both statements are correct. Statement I accurately identifies carbon dioxide as a meteorologically significant gas responsible for the greenhouse effect. Statement II provides the precise physical mechanism for this phenomenon. Carbon dioxide allows shortwave solar radiation to pass through to the Earth's surface but absorbs the outgoing longwave terrestrial radiation. This process of trapping heat is the definition of the greenhouse effect. Therefore, Statement II is the correct explanation for Statement I.

Question 4

Consider the following statements regarding the composition of the atmosphere:
1. Water vapour concentration in the atmosphere generally increases from the equator towards the poles.
2. Oxygen becomes almost negligible in quantity at a height of 90 km, while carbon dioxide is found up to 120 km from the Earth's surface.
3. The concentration of dust particles is typically higher in subtropical and temperate regions compared to equatorial and polar regions.
How many of the above statements are correct?

Accepted Answer

Only one. Statement 1 is incorrect. Water vapour concentration is highest in the warm and wet tropics near the equator and decreases towards the cold, dry polar regions. The statement reverses this spatial distribution. Statement 2 is incorrect. The altitudes are swapped. Oxygen becomes almost negligible at a height of 120 km, not 90 km. Conversely, carbon dioxide and water vapour are found only up to approximately 90 km from the Earth's surface. Statement 3 is correct. Due to factors like dry winds, the concentration of dust particles is generally higher in subtropical and temperate regions compared to the equatorial and polar regions. Therefore, only one statement is correct.

Question 5

Consider the following rows regarding components of the atmosphere:
Row 1: Component: Ozone | Characteristic: Found between 10 and 50 km and absorbs ultra-violet rays.
Row 2: Component: Dust Particles | Characteristic: Highest concentration found in equatorial and polar regions.
Row 3: Component: Water Vapour | Characteristic: Acts as hygroscopic nuclei for cloud formation.
In how many of the above rows is the given information correctly matched?

Accepted Answer

Only one row. Row 1 is correctly matched. The text states that ozone is found between 10 and 50 km above the earth’s surface and acts as a filter by absorbing ultra-violet rays. Row 2 is incorrectly matched. The text specifies that the higher concentration of dust particles is found in subtropical and temperate regions due to dry winds, not in equatorial and polar regions. This is a 'Spatial Swap' trap. Row 3 is incorrectly matched. The text states that 'Dust and salt particles act as hygroscopic nuclei around which water vapour condenses to produce clouds', not water vapour itself. This is a 'Terminology & Origin Swap' trap. Therefore, only one row is correctly matched.

Question 6

Consider the following pairs regarding atmospheric layers and their characteristic temperatures: 1. Tropopause over the equator: Approximately -80°C. 2. Stratopause: Approximately 0°C. 3. Mesosphere at 80 km altitude: Approximately -100°C. How many of the above pairs are correctly matched?

Accepted Answer

All three pairs. Statement 1 is correct. The temperature at the tropopause over the equator is approximately -80°C. This is due to the greater height of the troposphere (around 18 km) at the equator, leading to more significant adiabatic cooling. Statement 2 is correct. The stratosphere extends up to a height of 50 km. The temperature increases with altitude in this layer, reaching a maximum of approximately 0°C at its upper boundary, the stratopause. Statement 3 is correct. Within the mesosphere, which extends up to 80 km, the temperature decreases with altitude. It reaches the coldest point in the Earth's atmosphere, approximately -100°C, at the mesopause (80 km altitude). Since all three pairs are correctly matched, the correct option is (c).

Question 7

Consider the following statements regarding the structure of the atmosphere: 1. The thickness of the troposphere is greatest at the poles due to the intense subsidence of cold air. 2. The air temperature at the tropopause is significantly colder over the equator than it is over the poles. 3. In the ionosphere, temperature decreases with increasing altitude, a condition which allows for the reflection of radio waves back to Earth. How many of the above statements are correct?

Accepted Answer

Only one. Statement 1 is incorrect. The thickness of the troposphere is greatest at the equator (about 18 km), not the poles (about 8 km). This is because strong convectional currents at the equator transport heat to great heights. Statement 2 is correct. The tropopause is colder over the equator (about -80°C) than over the poles (about -45°C), a direct consequence of the greater tropospheric height and associated cooling at the equator. Statement 3 is incorrect. While the ionosphere reflects radio waves, the temperature in this layer increases with height.

Question 8

Consider the following statements regarding the structure of the atmosphere: 1. The thickness of the troposphere is greatest at the poles because heat is transported to great heights by strong convectional currents. 2. The temperature at the tropopause is colder over the equator than it is over the poles. 3. In the Mesosphere, temperature increases with an increase in altitude. How many of the above statements are correct?

Accepted Answer

Only one. Statement 1 is incorrect. It commits a 'Spatial Swap' trap. The text states that the thickness of the troposphere is greatest at the equator (18 km), not the poles (8 km), due to strong convectional currents transporting heat to great heights. Statement 2 is correct. The text specifies that the temperature at the tropopause is 'about minus 80°C over the equator and about minus 45°C over the poles'. Since -80°C is colder than -45°C, the statement is factually correct. Statement 3 is incorrect. It involves a 'Conceptual Reversal'. The text clearly states that in the Mesosphere, 'temperature starts decreasing with the increase in altitude'. Therefore, only one statement is correct.

Composition And Structure Of Atmosphere

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