Assertion (A): The acceleration due to gravity is less at the equator than at the poles. Reason (R): Earth's rotation causes a centrifugal effect that reduces effective gravity at the equator.
A. A is true, but R is false
B. Both A and R are true, but R is not the correct explanation of A
C. A is false, but R is true
D. Both A and R are true, and R is the correct explanation of A
Answer: Option D
Solution (By JKSSB Mock Tests)
Assertion is true: g is about 9.78 m/s² at equator vs 9.83 m/s² at poles. Reason is true and correctly explains A: Earth's rotation creates centrifugal acceleration outward, maximum at equator (radius of rotation = Earth's radius), reducing effective g. Additionally, equatorial bulge increases distance from center, further reducing g. Memory tip: 'Rotation effect: g_effective = g - ω²R cos²φ'. This assertion-reason question tests nuanced understanding of gravity variation, common in competitive exams. Always verify both statements independently before assessing the explanatory link.
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