# IAS Prelims Exam: Physical Geography NCERT Questions: SOLAR RADIATION, HEAT BALANCE AND TEMPERATURE

Physical Geography is a very important component of Civil Service Exam Syllabus and it helps immensely in the IAS Prelims Exam as a whole. 20 to 30% questions appear from the Geography section only and it can make a huge difference

Created On: Mar 16, 2016 14:18 IST

For the Civil Services IAS Exam Geography has vast and it covers most sections of the General Studies for the IAS Prelims Exam. The geography is scientific in its orientation and hence the IAS Aspirants having Arts background find it very difficult to prepare the geography for the IAS Prelims Exam.

Q.1. Consider the following statements

1.    Position of the earth farthest from the sun is called perihelion.

2. Perihelion and Aphelion is the position of the earth during its rotation on its axis,

Select the correct answer from the following codes

a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Explanation:  During its revolution around the sun,the earth is farthest from the sun (152 million km on 4th July). This position of the earth is called aphelion. On 3rd January, the earth is the nearest to the sun (147 million km). This position is called perihelion.

Q.2. Consider the following statements

1. The annual insolation received in January is more than July.
2. Solar output variation affects daliy weather changes in the surface of 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

Explanation: The annual insolation received by the earth on 3rd January during perilion is slightly more than the amount received on 4th July. However, the effect of this variation in the solar output is masked by other factors like the distribution of land and sea and the atmospheric circulation. Hence, this variation in the solar output does not have great effect on daily weather changes on the surface of the earth.

Q.3. Which of the following the factors have less influence on variation in insolation?

1. Rotation of earth on its axis
2. Angle of inclination of the sun’s rays
3. Transparency of the atmosphere

Select the correct answer from the following codes

a.Only 3
b.Only 1 and 2
c.Only 2 and 3
d.1,2 and 3

Explanation: The factors that cause these variations in insolation are : (i) the rotation of earth on its axis; (ii) the angle of inclination of the sun’s rays; (iii) the length of the day; (iv) the transparency of the atmosphere; (v) the configuration of land in terms of its aspect. The last two however, have less influence.

Q.4. Consider the following statements

1. Equator receives the highest insolation than any other latitudes.
2. In the same latitude amount of insolation is more over ocean than continent.

Select the correct answer from the following codes

a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Explanation: Maximum insolation is received over the subtropical deserts, where the cloudiness is the least. Equator receives comparatively less insolation than the tropics. Generally, at the same latitude the insolation is more over the continent than over the oceans. In winter, the middle and higher latitudes receive less radiation than in summer.

Q.5. With reference to heating and cooling of earth, which of the following is/are true?

1. Atmosphere is heated by shortwave radiation reflected from the surface of the earth.
2. Lower layers of atmosphere is heated by the process of conduction.
3. Transfer of heat through horizontal movement of air is called advection.

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

Explanation: The earth after being heated by insolation  transmits the heat to the atmospheric layers near to the earth in long wave form. Conduction takes place when two bodies of unequal temperature are in contact with one another, Conduction is important in heating the lower layers of the atmosphere. Process of vertical heating of the atmosphere is known as convection. The transfer of heat through horizontal movement of air is called advection.

Q.6. Consider the following statements

1. Convective transfer of energy is confined only to the troposphere and stratosphere.

2. The red colour of the rising and the setting sun is the result of scattering of light within the atmosphere.

Select the correct answer from the following codes

a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Explanation:  The red colour of the rising and the setting sun and the blue colour of the sky are the result of scattering of light within the atmosphere. Process of vertical heating of the atmosphere is known as convection. The convective transfer of energy is confined only to the troposphere.

Q.7. Which of the following is/are the result of advection process?

1. Diurnal variation
2. Loo winds in North India
3. Air currents

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

Explanation: In middle latitudes, most of dirunal (day and night) variation in daily weather is caused by advection alone. In tropical regions particularly in northern India during summer season local winds called ‘loo’ is the outcome of advection process. Winds are a result of advection, while air currents are a result of convection.

Q.8. Albedo of the earth refers to

a. Amount of radiation reflected by the earth
b. Amount of radiation reflected by clouds
c. Amount of radiation reflected by snow and ice covered areas.
d. Amount of radiation absorbed by earth

Explanation: Consider that the insolation received at the top of the atmosphere is 100 per cent.
Roughly 35 units are reflected back to space even before reaching the earth’s surface. Of these, 27 units are reflected back from the top of the clouds and 2 units from the snow and ice-covered areas of the earth. The reflected amount of radiation is called the albedo of the earth

Q.9. Higher latitudes are not permanently frozen because of

a. Presence of warm and cold currents
b. very less insolation
c. redistribution of surplus heat energy pole wards from tropics
d. Local aspects

Explanation: There is a surplus of net radiation balance between 40 degrees north and south and the
regions near the poles have a deficit. The surplus heat energy from the tropics is redistributed pole wards and as a result the tropics do not get progressively heated up due to the accumulation of excess heat or the high latitudes get permanently frozen due to excess deficit.

Q.10. Which of the following is/are not factors influencing temperature distribution?

1.  Latitude
2. Distance from sea
3. Local aspects

Select the correct answer from the following codes

a.Only 1
b.Only 1 and 2
c.Only 2 and 3
d.None

Explanation: The temperature of air at any place is influenced by (i) the latitude of the place; (ii) the altitude of the place; (iii) distance from the sea, the air mass circulation; (iv) the presence of warm and cold ocean currents; (v) local aspects.

Q.11. Consider the following statements

1. The variation in temperature over the sea is less compared to land.
2. The presence of warm ocean currents, Gulf Stream and Labrador current, make the Northern
Atlantic Ocean warmer

Select the correct answer from the following codes

a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2