IAS Prelims Exam: Physical Geography NCERT Questions: Landforms and the Climate

Q1. Which of the following is/are not influential factors for evolution of landforms?
1. Climate
2. Stability of sea level
3. Tectonic stability of land masses

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    None

Answer: d

Explanation: Many varieties of landforms develop by the action of each of the geomorphic agents
depending upon especially the type and structure i.e. folds, faults, joints, fractures, hardness and softness, permeability and impermeability come under structure of rocks. There are some other independent controls like (i) stability of sea level; (ii) tectonic stability of landmasses; (iii) climate, which influence the evolution of landforms.

Q2. Consider the following statements 1.    Over a period of time stream loses its velocity.
2. Depositional forms of running water associated with steeper slopes are greater than medium and gentler slopes.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: a

Explanation:  With time, stream channels over steep gradients turn gentler due to continued erosion, and as a consequence, lose their velocity, facilitating active deposition. There may be depositional forms associated with streams flowing over steep slopes. But these phenomena will be on a small scale compared to those associated with rivers flowing over medium to gentle slopes. The gentler the river channels in gradient or slope, the greater is the deposition.


Q3. Consider the following statements 
1. Width of gorge is equal in top and bottom.
2. A canyon is a variant of gorge.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: c

Explanation:  A gorge is almost equal in width at its top as well as its bottom. In contrast, a canyon is wider at its top than at its bottom. In fact, a canyon is a variant of gorge. Canyons commonly form in horizontal bedded sedimentary rocks and gorges form in hard rocks.

Q4. Consider the following statements 
1.    Carbon dioxide is transparent to the terrestrial radiation.
2.    Ozone is 50km above earth which absorbs and filters ultraviolet radiation.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: d

Explanation:  Carbon dioxide is meteorologically a very important gas as it is transparent to the incoming solar radiation but opaque to the outgoing terrestrial radiation. Ozone is another important component of the atmosphere found between 10 and 50 km above the earth’s surface and acts as a filter and absorbs the ultra-violet rays radiating from the sun and prevents them from reaching the surface of the earth.

Q5. Which of the following is/are true about water vapour?
1. Water vapour decreases with altitude.
2. Water vapour decreases from poles to equator.
3. It protects the earth from becoming too cold and too hot.

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: d

Explanation: Water vapour is also a variable gas in the atmosphere, which decreases with altitude. Water vapour also decreases from the equator towards the poles. It also absorbs parts of the insolation from the sun and preserves the earth’s radiated heat. It thus, acts like a blanket allowing the earth neither to become too cold nor too hot. Water vapour also contributes to the stability and instability in the air.

Q6. Consider the following statements 
1.    Dust particles are in higher concentration in temperate regions than equatorial regions.
2.    Clouds are produced by condensation of water vapour on dust and salt particles.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: c

Explanation:  Dust particles are generally concentrated in the lower layers of the atmosphere; yet, convectional air currents may transport them to great heights. The higher concentration of dust particles is found in subtropical and temperate regions due to dry winds in comparison to equatorial and Polar Regions. Dust and salt particles act as hygroscopic nuclei around which water vapour condenses to produce clouds.

Q7. Which of the following is/ are true about troposphere?
1. Troposhere is thick near equator than poles.
2. It contains water vapour and dust particles.
3. Temperature in this layer increases with altitude.

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: b

Explanation: Thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents. This layer contains dust particles and water vapour.
All changes in climate and weather take place in this layer. The temperature in this layer decreases at the rate of 1°C for every 165m of height.

Q8. Consider the following statements 
1. Zone separating troposphere and mesosphere is tropopause.
2. Temperature of tropopause is the same at equator and poles.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: d

Explanation: The zone separating the troposphere from stratosphere is known as the tropopause. The air temperature at the tropopause is about minus 800C over the equator and about minus 450C over the poles. The temperature here is nearly constant, and hence, it is called the tropopause. 

Q9. Which of the following is/are true about stratosphere?
1. This is the most important layer for all biological activity.
2. It contains ozone layer.
3.    Temperature increases with altitude.

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: c

Explanation: The stratosphere is found above the tropopause and extends up to a height of 50 km. One important feature of the stratosphere is that it contains the ozone layer. This layer absorbs ultra-violet radiation and shields life on the earth from intense, harmful form of energy. Troposphere is the most important layer for all biological activity.

Q10. Consider the following statements 
1. Ionosphere is located 80-400km below mesopause.
2. Ionosphere is responsible for radio wave transmission from earth.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: b

Explanation:  The ionosphere is located between 80 and 400 km above the mesopause. It contains electrically charged particles known as ions, and hence, it is known as ionosphere. Radio waves transmitted from the earth are reflected back to the earth by this layer. Temperature here starts increasing with height.

Q11. Consider the following statements 
1. The highest layer in the atmosphere is mesosphere.
2. Temperature in mesosphere increases with altitude.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: d

Explanation:  The uppermost layer of the atmosphere above the ionosphere is known as the exosphere. This is the highest layer but very little is known about it. Whatever contents are there, these are extremely rarefied in this layer, and it gradually merges with the outer space.