SEBA Class 9 Social Science Geography Chapter 2 Atmosphere: Structure, Air Pressure and Wind System MCQs (2026–27) – Assam Eduverse

Q21. Assertion (A): Air pressure decreases with increase in altitude.
Reason (R): The amount of air decreases with height.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q22. Assertion (A): The equatorial region is a low pressure belt.
Reason (R): Air gets heated and rises in this region.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q23. Assertion (A): There is no deflection of wind at the equator.
Reason (R): Coriolis force is zero at the equator.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q24. Assertion (A): The stratosphere is suitable for flying jet aircraft.
Reason (R): This layer is almost free from weather disturbances.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q25. Assertion (A): Wind speed increases when pressure gradient increases.
Reason (R): Greater pressure difference causes faster air movement.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q26. Assertion (A): The thermosphere is also called ionosphere.
Reason (R): This layer contains electrically charged particles.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q27. Assertion (A): Polar regions are high pressure areas.
Reason (R): The air in polar regions is very cold and heavy.
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 false
d) A is false but R is true
Answer: a) Both A and R are true and R is the correct explanation of A

Q28. Assertion (A): Wind direction is named after the direction towards which it blows.
Reason (R): A wind blowing from west to east is called westerly wind.
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 false
d) A is false but R is true
Answer: d) A is false but R is true

Q29. Assertion (A): Frictional force increases wind speed.
Reason (R): Friction opposes the movement of air.
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 false
d) A is false but R is true
Answer: d) A is false but R is true

Q30. Assertion (A): Ozone absorbs harmful ultraviolet rays.
Reason (R): Ozone layer is found mainly in the troposphere.
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 false
d) A is false but R is true
Answer: c) A is true but R is false

Q31. The main gases of the atmosphere are:
i) Nitrogen
ii) Oxygen
iii) Carbon dioxide
iv) Helium
a) i, ii and iii
b) i and ii
c) ii and iv
d) i, ii, iii and iv
Answer: a) i, ii and iii

Q32. The layers of the atmosphere include:
i) Troposphere
ii) Stratosphere
iii) Mesosphere
iv) Lithosphere
a) i and ii
b) i, ii and iii
c) ii and iv
d) i, ii, iii and iv
Answer: b) i, ii and iii

Q33. Weather phenomena occur in the troposphere such as:
i) Rain
ii) Clouds
iii) Storms
iv) Meteors burning
a) i and ii
b) i, ii and iii
c) ii and iv
d) i, ii, iii and iv
Answer: b) i, ii and iii

Q34. The factors affecting wind movement include:
i) Pressure gradient force
ii) Gravitational force
iii) Centrifugal force
iv) Frictional force
a) i, ii and iii
b) i, iii and iv
c) i, ii, iii and iv
d) ii and iv
Answer: c) i, ii, iii and iv

Q35. The global pressure belts are:
i) Equatorial low pressure belt
ii) Sub-tropical high pressure belt
iii) Sub-polar low pressure belt
iv) Polar high pressure belt
a) i and ii
b) i, ii and iii
c) ii and iv
d) i, ii, iii and iv
Answer: d) i, ii, iii and iv

Q36. Air pressure varies due to:
i) Air temperature
ii) Altitude
iii) Rotation of earth
iv) Distribution of land and water
a) i and ii
b) i, ii and iv
c) ii and iii
d) i, ii, iii and iv
Answer: b) i, ii and iv

Q37. Characteristics of the stratosphere include:
i) Presence of ozone layer
ii) Increase of temperature with height
iii) Weather activities
iv) Suitable for jet aircraft
a) i and ii
b) ii and iii
c) i, ii and iv
d) i, ii, iii and iv
Answer: c) i, ii and iv

Q38. Coriolis force causes:
i) Deflection of winds
ii) Right deflection in Northern Hemisphere
iii) Left deflection in Southern Hemisphere
iv) No effect at equator
a) i and ii
b) i, ii and iii
c) i, ii, iii and iv
d) ii and iv
Answer: c) i, ii, iii and iv

Q39. Beaufort Scale indicates:
i) Wind velocity
ii) Nature of wind
iii) Impact of wind
iv) Air pressure
a) i and ii
b) i, ii and iii
c) ii and iv
d) i, ii, iii and iv
Answer: b) i, ii and iii

Q40. Permanent winds include:
i) Trade winds
ii) Westerlies
iii) Polar winds
iv) Local winds
a) i and ii
b) i, ii and iii
c) ii and iv
d) i, ii, iii and iv
Answer: b) i, ii and iii