UPSC Prelims 2003 Q107: Geography – Physical Geography & Geomorphology
Assertion (A): The weight of a body decreases with the increase of latitude on earth.
Reason (R): The earth is not a perfect sphere.
- (a) Both A and R are individually true and R is the correct explanation of A
- (b) Both A and R are individually 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
Explanation
Weight of a body and latitude
| Part | Verdict |
|---|---|
| A. The weight of a body decreases with increase of latitude | False: weight increases from the equator to the poles |
| R. The earth is not a perfect sphere | True — it bulges at the equator |
A is false because g is greater at the poles, so weight rises with latitude; R is true.
Answer: (d) A is false but R is true.
Why each option is right or wrong
- (a) Incorrect. A is false, so R cannot explain it.
- (b) Incorrect. A is false, as weight increases with latitude.
- (c) Incorrect. R is true, so this code is wrong.
- (d) CORRECT. A is false because weight increases with latitude, while R is true.
Key point
g at the equator 9.78, at the poles 9.83 m/s2: polar radius is smaller.
Remember
A body weighs more at the poles than at the equator.
Common mistakes
- Thinking weight is less at the poles.
- Forgetting the equatorial bulge of the earth.
- Ignoring the earth's rotation effect.
Exam tip
Higher latitude: smaller radius, larger g, more weight.
Sources
- NCERT Class XI Physics — Gravitation
- H. C. Verma — Concepts of Physics, Volume 1 (Gravitation: variation of g with latitude)