Class 9 Insolation Mock Test (ICSE)

Topics in Insolation

• Insolation and heat budget
• Factors affecting temperature
• Temperature inversion
• Distribution of temperature

Insolation practice questions with answers

1. Q1Multiple choice·1 mark
   Which of the following best explains why temperature decreases with an increase in altitude?

   1. (a)Greater distance from the Prime Meridian
   2. (b)Thin air at higher altitudes which absorbs less heat from terrestrial radiation
   3. (c)High velocity of mountain winds
   4. (d)Lower angle of incidence of the sun's rays
   Show answer and step marks

   1. Correct option: (b) Thin air at higher altitudes which absorbs less heat from terrestrial radiation+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   The accumulation of dense, cold air at the bottom of a mountain valley, leading to frost formation while upper slopes remain warmer, is primarily caused by:

   1. (a)Adiabatic heating of descending maritime winds
   2. (b)Surface temperature inversion
   3. (c)Normal lapse rate operating at high elevations
   4. (d)Intense daytime insolation on valley floors
   Show answer and step marks

   1. Correct option: (b) Surface temperature inversion+1

   Answer: (b)
3. Q3Multiple choice·1 mark
   The fraction of incoming solar radiation reflected back directly from the earth's surface, particularly by snow and ice, is called:

   1. (a)Heat budget
   2. (b)Terrestrial radiation
   3. (c)Insolation
   4. (d)Albedo
   Show answer and step marks

   1. Correct option: (d) Albedo+1

   Answer: (d)
4. Q4Multiple choice·1 mark
   Lines drawn on a map connecting places having equal temperatures reduced to sea level are called:

   1. (a)Isohyets
   2. (b)Contours
   3. (c)Isotherms
   4. (d)Isobars
   Show answer and step marks

   1. Correct option: (c) Isotherms+1

   Answer: (c)
5. Q5Short answer·2 marks
   Give two geographical reasons why places located near the coast experience a moderate climate throughout the year compared to places situated in the interior of continents.
   Show answer and step marks

   1. First reason, any one of: water heats up and cools down more slowly than land, so the sea stays cooler than the land in summer and warmer in winter; winds blowing from the sea carry this moderating influence onto the coast, cooling it in summer and warming it in winter; sea breezes by day and land breezes by night reduce the daily range of temperature; or any other valid reason.+1
   2. Second reason, a different one from the same list.+1

   Answer: Any two of: water heats and cools more slowly than land, so the sea is cooler in summer and warmer in winter; onshore winds carry this moderating effect to the coast; land and sea breezes reduce the daily temperature range.
6. Q6Long answer·4 marks
   Answer the following questions regarding temperature inversion: (a) Define temperature inversion. [1] (b) State any two ideal conditions necessary for the occurrence of temperature inversion. [2] (c) Mention one adverse effect of temperature inversion on the lower atmosphere or human life. [1]
   Show answer and step marks

   1. (a) Temperature inversion is a condition in which temperature increases with height instead of decreasing, reversing the normal lapse rate.+1
   2. (b) First condition, any one of: long winter nights allowing rapid loss of heat from the ground; a clear, cloudless sky; calm or still air that prevents mixing; dry air; snow-covered ground; valleys or basins into which cold, dense air drains; or any other valid condition.+1
   3. (b) Second condition, a different one from the same list.+1
   4. (c) Any one of: pollutants, smoke and dust are trapped near the ground, forming smog that harms health; fog reduces visibility and disrupts road, rail and air transport; frost in valleys damages crops; or any other valid adverse effect.+1

   Answer: (a) Temperature increasing with height instead of decreasing. (b) Any two of: long winter nights, clear skies, calm air, dry air, snow-covered ground, valleys where cold air drains. (c) Any one of: pollutants trapped near the ground forming smog; fog reducing visibility; frost damaging crops.

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