2025
Q1. Two satellites revolve around Earth in circular orbits of radii R and 4R. The ratio of their orbital speeds is:
(a) 1 : 4
(b) 2 : 1
(c) 1 : 2
(d) 4 : 1
Answer: (b)
Solution: v=GM/R⇒v∝1/R.
So, v1/v2=4R/R=2
Q2. If the mass of Earth suddenly becomes four times, acceleration due to gravity at surface becomes:
(a) g
(b) 2g
(c) 4g
(d) g/4
Answer: (c)
g=GM/R2
🟢 2024
Q3. Escape velocity from a planet depends on:
(a) Mass only
(b) Radius only
(c) Mass and radius
(d) Density only
Answer: (c)
Q4. A body is taken to a height equal to Earth’s radius. Value of g becomes:
(a) g
(b) g/2
(c) g/3
(d) g/4
Answer: (d)
g′=g/(1+h/R)2=g/4
🟢 2023
Q5. Gravitational potential at infinity is taken as:
(a) 1
(b) –1
(c) 0
(d) ∞
Answer: (c)
Q6. If distance between two masses is halved, gravitational force becomes:
(a) F/2
(b) F
(c) 2F
(d) 4F
Answer: (d)
🟢 2022
Q7. Orbital period of satellite depends on:
(a) Mass of satellite
(b) Radius of orbit
(c) Shape of satellite
(d) Density of satellite
Answer: (b)
Q8. Weight of a body at centre of Earth is:
(a) mg
(b) infinite
(c) zero
(d) half
Answer: (c)
🟢 2021
Q9. Gravitational field intensity unit is:
(a) N
(b) N/kg
(c) J/kg
(d) kg/N
Answer: (b)
Q10. Geostationary satellite must have time period equal to:
(a) 12 hr
(b) 24 hr
(c) 6 hr
(d) 48 hr
Answer: (b)
🟢 2020
Q11. Escape velocity from Earth surface is approximately:
(a) 7.9 km/s
(b) 9.8 km/s
(c) 11.2 km/s
(d) 15 km/s
Answer: (c)
Q12. Potential energy between two masses is:
(a) Positive
(b) Zero
(c) Negative
(d) Infinite
Answer: (c)
🟢 2019
Q13. If Earth’s radius decreases keeping mass constant, g will:
(a) decrease
(b) increase
(c) remain same
(d) zero
Answer: (b)
Q14. Total energy of satellite in circular orbit is:
(a) Positive
(b) Zero
(c) Negative
(d) Infinite
Answer: (c)
🟢 2018
Q15. Gravitational force is:
(a) Contact force
(b) Repulsive
(c) Always attractive
(d) Depends on medium
Answer: (c)
Q16. Kepler’s third law states:
(a) T ∝ R
(b) T² ∝ R³
(c) T ∝ R²
(d) T³ ∝ R²
Answer: (b)
🟢 2017
Q17. Acceleration due to gravity at poles is:
(a) Maximum
(b) Minimum
(c) Zero
(d) Same everywhere
Answer: (a)
Q18. Gravitational constant (G) dimension is:
(a) ML²T⁻²
(b) M⁻¹L³T⁻²
(c) ML³T⁻¹
(d) M²L³T⁻²
Answer: (b)
🟢 2016
Q19. Weightlessness in satellite is due to:
(a) No gravity
(b) Zero mass
(c) Free fall motion
(d) High speed
Answer: (c)
Q20. At what depth does g become half?
(a) R/2
(b) R
(c) R/4
(d) R/3
Answer: (a)
🟢 2015
Q21. If Earth stops rotating, weight at equator will:
(a) decrease
(b) increase
(c) zero
(d) same
Answer: (b)
Q22. Binding energy of satellite equals:
(a) KE
(b) PE
(c) – Total energy
(d) 2KE
Answer: (c)
🟢 2014
Q23. Relation between escape velocity and orbital velocity:
(a) Ve = Vo
(b) Ve = √2 Vo
(c) Ve = Vo/2
(d) Ve = 2Vo
Answer: (b)
Q24. If distance doubles, potential becomes:
(a) Half
(b) Double
(c) Same
(d) Four times
Answer: (a)
🟢 2013
Q25. SI unit of gravitational potential is:
(a) N
(b) J
(c) J/kg
(d) N/kg
Answer: (c)
Q26. Value of g decreases with altitude because:
(a) Mass decreases
(b) Radius increases
(c) Density changes
(d) G changes
Answer: (b)