Air — Class 7 Social Science

Take a timed mock test to prepare for your exams.

Chapter Mock Test

Total Marks:40
Duration:45 min
Total Questions:20
Difficulty:Mixed

Test Structure

  • Section A: 10 MCQs (1 mark each)
  • Section B: 6 Short Answer (3 marks each)
  • Section C: 2 Long Answer (5 marks each)

Before taking the test

  • Know the composition: Nitrogen 78%, Oxygen 21%, Other gases 1% (CO₂, Argon, Ozone, Water vapour)
  • Remember five layers in order: Troposphere (weather), Stratosphere (ozone), Mesosphere (meteorites), Thermosphere (radio waves), Exosphere (satellites)
  • Distinguish weather (day-to-day, changes frequently) from climate (average over 25–30 years, stable)
  • Temperature decreases with height (6.5°C per km) and from equator to poles
  • Wind blows from HIGH pressure to LOW pressure; hot areas = low pressure, cold areas = high pressure
  • Three types of winds: Permanent (trade winds, westerlies, polar easterlies), Seasonal (monsoons), Local (land/sea breeze, loo)
  • Sea breeze = day (sea to land); Land breeze = night (land to sea)
  • Know the process: Evaporation then Condensation then Precipitation (rain, snow, sleet, hail)
  • Three types of rainfall: Convectional (equatorial, heavy with thunder), Orographic (mountains, windward vs leeward), Cyclonic (warm meets cold air)
  • Orographic rainfall: Windward side = heavy rain; Leeward side = rain shadow (dry). Example: Western Ghats

Key Concepts to Remember

Atmosphere Composition

Nitrogen 78% + Oxygen 21% + Other gases 1% (CO₂ greenhouse effect, Ozone UV protection)

Atmosphere Layers

Troposphere (weather) then Stratosphere (ozone) then Mesosphere (meteorites) then Thermosphere (radio) then Exosphere (satellites)

Wind Direction

High Pressure to Low Pressure = Wind. Hot = Low Pressure (air rises). Cold = High Pressure (air sinks)

Types of Rainfall

Convectional (Sun heats ground) + Orographic (mountain barrier) + Cyclonic (warm meets cold air)