1. The net radiation balance records a surplus between which of the following latitudes?
(a) ~40°N to 25°S
(b) ~40°N to 40°S
(c) ~40°N to 20°N
(d) ~40°N to 20°S
Incoming Solar radiation is in the form of Shortwave Infrared radiation. Atmosphere let’s this pass through, which is then absorbed by earth and re-emitted back into atmosphere in the form of longwave infrared radiation. This is absorbed by atmosphere, and commonly known as Greenhouse Effect. This way our atmosphere gets heated in bottoms-up manner.
The net latitudinal radiation balance records a surplus between ~40oN to 40oS latitudes. Here, the incoming solar insolation is higher than the heat loss due to long wave radiation emission from the earth. Poleward from these latitudes, there is net loss of heat due to low incoming solar radiation.
Solar insolation at higher latitudes is low because of high slant angle of incoming sun rays.
2. Consider the following pairs:
Factor Impacting : Temperature Impact
1. Altitude : Higher the altitude, higher the temperature.
2. Latitude : Higher the latitude, lower the temperature. 3. Distance from the Sea : Coastal areas have less variation in mean temperatures than inland areas.
Which of the pairs given above is/are correctly matched?
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 3 only
The mean temperature of atmosphere decreases with altitude. On an average, the temperature decreases by 6.5oC per 1000 m increase in height. (Natural Lapse Rate) The mean temperature decreases with increase in latitude. This is due to progressive reduction in solar insolation with an increase in latitude of a place.
The coastal areas have a more moderate climate due to impact of land and sea breeze that reduce diurnal variation (daily temperate range at a place) in mean temperature.
3. Consider the following statements:
Assertion (A): Isotherms trending from oceans to land shift poleward during summers.
Reason (R): Land gets heated more quickly compared to oceans.
Select the correct answer using the code given below:
(a) Both (A) and (R) are true and (R) is the correct explanation of (A). (b) Both (A) and (R) are true but (R) is not the correct explanation of (A). (c) (A) is true but (R) is wrong.
(d) (A) is wrong but (R) is true.
Specific Heat of water is high as compared to Land. Higher the Specific heat, more is the time taken to get heated or to Cool down.
Land gets heated or cooled quickly compared to Oceans. Hence, during summers, at same latitude, the land has higher temperature compared to the ocean. For example, if mean temperature at 25oN latitude above ocean is 25oC, then the temperature at same latitude over land would be higher, say 28oC. We know that mean temperature declines as we move poleward. So, temperature of 25oC over land would be recorded at some higher latitude say 30oN. This causes the poleward shift in 25oC isotherm (25oN over Ocean, 30oN over land).
4. Consider the following statements regarding various types of soil found in India:
(1) Black soil has a property of ‘self-ploughing’ in dry season.
(2) Yellow soil looks red when it occurs in a hydrated form.
(3) Red laterite soils are more suitable for tree crops like cashew nuts.
Which of the statements given above are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
The thin layer of grainy substance covering the surface of the earth is called soil. Soil is made up of organic matter, minerals and weathered rocks.
Black Soil: is also known as Regur Soil. They are generally clayey, deep and impermeable. They swell and become sticky when wet and stink when dried. So, during the dry season, this soil develops wide cracks. Thus, there occurs a kind of ‘self ploughing’. Thus, statement 1 is correct.
Red and Yellow soil: The red soil appears reddish colour due to wide diffusion of iron in crystalline and metamorphic rocks. It looks yellow when it occurs in a hydrated form. They are generally poor in nitrogen, phosphorus and humus. Thus, statement 2 is incorrect. Laterite soil: They develop in areas with high temperature and high rainfall. These are result of intense leaching due to tropical rains. Humus content in the soil is removed fast by bacteria that thrives well in high temperature. Red laterite soils in Tamil Nadu, Andhra Pradesh and Kerala are more suitable for tree crops like cashew nuts. Thus, statement 3 is correct.
5. Consider the following pairs:
Rock : Example
1. Sedimentary : Limestone
2. Igneous : Shale
3. Metamorphic : Granite
Which of the pairs given above is/are matched correctly?
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) None of the above
The earth’s crust is composed of rocks. A rock is an aggregate of one or more minerals. Rock may be hard or soft and in varied colours.
Sedimentary rocks: The word ‘sedimentary’ is derived from the Latin word sedimentum, which means settling. Depending upon the mode of formation, sedimentary rocks are classified into three major groups:
o mechanically formed — sandstone, conglomerate, limestone, shale, loess etc. are examples;
o organically formed — geyserite, chalk, limestone, coal etc. are some examples; o chemically formed — chert, limestone, halite, potash etc. are some examples. Igneous Rocks: As igneous rocks form out of magma and lava from the interior of the earth, they are known as primary rocks. Igneous rocks are classified based on texture. Texture depends upon size and arrangement of grains or other physical conditions of the materials. If molten material is cooled slowly at great depths, mineral grains may be very large. Sudden cooling (at the surface) results in small and smooth grains. Intermediate conditions of cooling would result in intermediate sizes of grains making up igneous rocks. Granite, gabbro, pegmatite, basalt, volcanic breccia and tuff are some of the examples of igneous rocks.
Metamorphic Rocks: The word metamorphic means ‘change of form’. These rocks form under the action of pressure, volume and temperature (PVT) changes. Gneissoid, granite, syenite, slate, schist, marble, quartzite etc. are some examples of metamorphic rocks.