The universal law of gravitation states that the force between two masses is directly proportional to:
A. Square of the distance between them
B. Product of the masses
C. Sum of the masses
D. Difference of the masses
Answer: Option B
Solution (By JKSSB Mock Tests)
Newton's law of gravitation: F = G·m₁m₂/r². Thus force is directly proportional to the product of the masses (m₁m₂) and inversely proportional to square of distance (r²). Option D incorrectly states 'directly proportional to square of distance' – it's inverse square. This fundamental law governs celestial mechanics. Memory tip: 'F ∝ m₁m₂ and F ∝ 1/r²'. Competitive exams often test precise wording of physical laws; distractors may reverse proportionality or misstate dependencies. Always recall the exact mathematical form.
Explanation:
Generator: coil rotated in magnetic field induces emf. Motor: opposite. Transformer: changes voltage, no moving parts. Rectifier: AC to DC.
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