Class 9 Atmosphere and Climate Mock Test (CBSE)

Topics in Atmosphere and Climate

• Composition of the atmosphere
• Structure of the atmosphere
• Weather and climate
• Elements of weather and climate
• Seasons in India
• Monsoon
• Climate change
• Floods case study

Atmosphere and Climate practice questions with answers

1. Q1Multiple choice·1 mark
   Which layer of the atmosphere contains the ozone layer, which absorbs harmful ultraviolet radiation from the Sun?

   1. (a)Thermosphere
   2. (b)Stratosphere
   3. (c)Mesosphere
   4. (d)Troposphere
   Show answer and step marks

   1. Correct option: (b) Stratosphere. Identify the atmospheric layer that houses the ozone layer responsible for absorbing UV rays: Stratosphere.+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   What term is used to describe the average weather pattern taken over a long period of time, usually 30 years or more, for a specific region?

   1. (a)Climate
   2. (b)Atmosphere
   3. (c)Season
   4. (d)Weather
   Show answer and step marks

   1. Correct option: (a) Climate. Differentiate between short-term atmospheric conditions (weather) and long-term average patterns (climate).+1

   Answer: (a)
3. Q3Multiple choice·1 mark
   In which atmospheric layer does temperature generally decrease with increasing altitude, and where virtually all weather phenomena such as clouds, precipitation, and storms take place?

   1. (a)Stratosphere
   2. (b)Mesosphere
   3. (c)Troposphere
   4. (d)Thermosphere
   Show answer and step marks

   1. Correct option: (c) Troposphere. Identify the lowest layer of the atmosphere containing water vapour and weather activity as the troposphere.+1

   Answer: (c)
4. Q4Short answer·3 marks
   Explain the mechanism of the onset of the monsoon in India by highlighting any three major factors responsible for it.
   Show answer and step marks

   1. First factor, any one of: differential heating and cooling of land and sea creates low pressure over the Indian landmass and high pressure over the surrounding seas; the shift of the ITCZ in summer over the Ganga plain (the monsoon trough); the high-pressure area east of Madagascar (about $20^\circ$S over the Indian Ocean); intense heating of the Tibetan Plateau in summer, producing strong vertical air currents and low pressure; the northward movement of the westerly jet stream beyond the Himalayas and the tropical easterly jet stream over the Indian Peninsula; or any other valid factor.+1
   2. Second factor, a different one from the same list.+1
   3. Third factor, a different one from the same list.+1

   Answer: Any three of: differential heating of land and sea; shift of the ITCZ over the Ganga plain in summer; high pressure east of Madagascar; intense summer heating of the Tibetan Plateau; movement of the westerly jet stream north of the Himalayas and the tropical easterly jet over the peninsula.

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