Q1.
A planet has twice the mass and twice the radius of Earth. Surface gravity:
A) g/2
B) g
C) 2 g
D) g/4
Q2.
A satellite in circular orbit at height h has orbital speed v. If height is doubled, speed becomes:
A) v/√2
B) v/2
C) v√2
D) v
Q3.
Two spheres of masses 2 kg and 8 kg, distance 1 m. Gravitational force:
A) 1.33 × 10⁻¹⁰ N
B) 10⁻¹⁰ N
C) 2 × 10⁻¹⁰ N
D) 4 × 10⁻¹⁰ N
Q4.
A planet has density 8×10³ kg/m³. Universal gravitation constant G=6.67×10⁻¹¹. Find surface gravity:
A) 5.34 m/s²
B) 6.67 m/s²
C) 8 m/s²
D) 10 m/s²
Q5.
Escape velocity on a planet is 11 km/s. Surface gravity g=10 m/s². Radius of planet:
A) 6.05 ×10⁶ m
B) 1.21 ×10⁷ m
C) 5 ×10⁶ m
D) 2 ×10⁷ m
Q6.
Gravitational potential energy of 2 kg and 3 kg mass, 1 m apart:
A) –4×10⁻¹¹ J
B) –8×10⁻¹¹ J
C) –6×10⁻¹¹ J
D) –2×10⁻¹¹ J
Q7.
A satellite moves in elliptical orbit with semi-major axis a. Period of revolution:
A) T∝a3/2
B) T∝a2
C) T∝√a
D) T∝1/a
Q8.
Height above Earth where g is half of surface value:
A) R
B) 2R
C) √2 R
D) 3R
Q9.
Two planets have same mass. Ratio of surface gravities = 4. Ratio of radii:
A) 1/2
B) 1/4
C) 2
D) 4
Q10.
Gravitational field at midpoint between 2 equal masses 5 kg each, separated 2 m:
A) 0 N/kg
B) 16.675×10⁻¹⁰ N/kg
C) 8.34×10⁻¹⁰ N/kg
D) 10⁻¹⁰ N/kg
Q11.
Moon of mass M, radius R, satellite in circular orbit of radius 2R. Orbital speed:
A) √(GM/2R)
B) √(GM/R)
C) √(GM/4R)
D) √(2GM/R)
Q12.
Two stars of masses 2×10³⁰ kg & 3×10³⁰ kg separated by 1×10¹¹ m. Gravitational force:
A) 4 × 10²² N
B) 2 × 10²² N
C) 6 × 10²² N
D) 3 × 10²² N
Q13.
Earth satellite, period 12 h. Orbital radius:
A) 4.2 ×10⁷ m
B) 1.5 ×10⁷ m
C) 3.84 ×10⁷ m
D) 6 ×10⁷ m
Q14.
Acceleration due to gravity inside Earth at depth h (uniform density):
A) g(1 – h/R)
B) g(1 – h/R)²
C) g(1 – h²/R²)
D) g(1 – 2h/R)
Q15.
Weight of body at Earth’s equator vs pole:
A) Pole > Equator
B) Equator > Pole
C) Same
D) Depends on mass
Q16.
Gravitational potential energy of a uniform sphere of mass M, radius R:
A) –3/5 GM²/R
B) –GM²/2R
C) –GM²/R
D) –2GM²/5R
Q17.
Escape velocity from Earth = 11.2 km/s. If radius reduced to half, escape velocity:
A) 7.9 km/s
B) 11.2 km/s
C) 15.8 km/s
D) 22.4 km/s
Q18.
Two masses 2 kg & 8 kg, free to move under mutual gravitation. Acceleration of 2 kg mass:
A) 1.67×10⁻¹⁰ m/s²
B) 3.34×10⁻¹⁰ m/s²
C) 8×10⁻¹¹ m/s²
D) 4×10⁻¹¹ m/s²
Q19.
Orbital velocity of satellite at Earth’s surface:
A) 7.9 km/s
B) 11.2 km/s
C) 3.5 km/s
D) 5.6 km/s
Q20.
Two satellites in circular orbits of radii R and 4R. Ratio of orbital speeds:
A) 1:2
B) 2:1
C) 1:4
D) 4:1
Q21.
Gravitational field inside uniform spherical shell:
A) Zero
B) GM/r²
C) GM/R²
D) GM/2R²
Q22.
Satellite orbiting Earth, period T. If mass of satellite doubled, T:
A) Same
B) Doubled
C) Halved
D) √2 times
Q23.
Two planets, M₁, M₂, distance d. Gravitational potential at midpoint:
A) –G(M₁+M₂)/d
B) –G(M₁+M₂)/(2d)
C) –GM₁/d – GM₂/d
D) –G√(M₁M₂)/d
Q24.
A tunnel through Earth along diameter, body released. Time period of oscillation:
A) 84 min
B) 42 min
C) 53 min
D) 24 min
Q25.
A planet of mass M, radius R, rotates. Satellite orbits just above surface. Period:
A) 2π √(R/g)
B) √(2π R/g)
C) 2π √(g/R)
D) 2π √(GM/R²)
Answer
| Question No. | Answer |
|---|---|
| 1 | A |
| 2 | A |
| 3 | A |
| 4 | B |
| 5 | A |
| 6 | C |
| 7 | A |
| 8 | A |
| 9 | A |
| 10 | A |
| 11 | A |
| 12 | A |
| 13 | A |
| 14 | C |
| 15 | A |
| 16 | A |
| 17 | C |
| 18 | B |
| 19 | A |
| 20 | B |
| 21 | A |
| 22 | A |
| 23 | B |
| 24 | B |
| 25 | A |