physics : class11 Newton's Law of Gravitation : Gravitational Force : Gravitation MCQ Questions and Answers
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Newton's Law of Gravitation
MCQ questions and answers.
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MCQ Questions
1. According to Newton's law of gravitation, the gravitational force between two bodies is directly proportional to the product of their masses and inversely proportional to the:
A.
Sum of their masses
B.
Square of the distance between their centers
C.
Difference between their masses
D.
Cube of the distance between their centers
Correct Answer:
Square of the distance between their centers
Explanation:
Newton's law of gravitation is expressed as F = Gm1m2/r², so the force is inversely proportional to the square of the distance between the centers of the two bodies.
2. Which expression represents Newton's law of universal gravitation for two masses m1 and m2 separated by distance r?
A.
F = G(m1 + m2)/r
B.
F = Gm1m2/r²
C.
F = Gm1m2r²
D.
F = (m1m2)/(Gr²)
Correct Answer:
F = Gm1m2/r²
Explanation:
The magnitude of the gravitational force is given by F = Gm1m2/r², where G is the universal gravitational constant.
3. If the mass of one body is doubled while the other mass and the distance between them remain unchanged, the gravitational force becomes:
A.
Half
B.
One-fourth
C.
Double
D.
Unchanged
Correct Answer:
Double
Explanation:
Since gravitational force is directly proportional to each mass, doubling one mass doubles the force.
4. If the distance between two bodies is doubled, their gravitational force becomes:
A.
Four times
B.
Twice
C.
Half
D.
One-fourth
Correct Answer:
One-fourth
Explanation:
The force varies inversely as the square of the distance. Replacing r by 2r gives F/(2²) = F/4.
5. The gravitational force between two bodies acts along the:
A.
Tangent to their surfaces
B.
Line joining their centers
C.
Vertical direction only
D.
Direction of motion of the bodies
Correct Answer:
Line joining their centers
Explanation:
Newton's law states that the gravitational force acts along the line joining the centers of the two interacting bodies.
6. What is the SI unit of the universal gravitational constant G?
A.
N m² kg⁻²
B.
N kg² m⁻²
C.
kg m² N⁻¹
D.
N m kg⁻¹
Correct Answer:
N m² kg⁻²
Explanation:
From G = Fr²/(m1m2), the SI unit of G is N m² kg⁻².
7. If both masses are doubled while the distance between them remains unchanged, the gravitational force becomes:
A.
Twice
B.
Four times
C.
Half
D.
Unchanged
Correct Answer:
Four times
Explanation:
The force is proportional to m1m2. Doubling both masses changes their product by 2 × 2 = 4, so the force becomes four times.
8. Newton's law of gravitation applies to:
A.
Only objects on Earth
B.
Only planets and stars
C.
Any two bodies having mass
D.
Only electrically charged bodies
Correct Answer:
Any two bodies having mass
Explanation:
Every pair of bodies with mass exerts a gravitational force on each other, according to Newton's law of universal gravitation.
9. If the distance between two masses is reduced to half its original value, the gravitational force becomes:
A.
Half
B.
Twice
C.
Four times
D.
One-fourth
Correct Answer:
Four times
Explanation:
Because F is inversely proportional to r², changing the distance to r/2 gives F' = F/(1/2)² = 4F.
10. The gravitational force exerted by one body on another is:
A.
Always repulsive
B.
Always attractive
C.
Zero for massive bodies
D.
Attractive only when the bodies are moving
Correct Answer:
Always attractive
Explanation:
Newtonian gravitational force between two masses is always attractive and acts along the line joining their centers.
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