# Class 9 Science MCQ Chapter 10 Gravitation

Class 9 Science MCQ Chapter 10 Gravitation, Class 9 Science MCQ Question Answer, Class 9 Science Multiple Choice Question Answer to each chapter is provided in the list of SCERT Science Class 9 Objective Types Question Answer so that you can easily browse through different chapters and select needs one. Class 9 Science MCQ Chapter 10 Gravitation Question Answer can be of great value to excel in the examination.

## SCERT Class 9 Science MCQ Chapter 10 Gravitation

SCERT Class 9 Science MCQ Chapter 10 Gravitation Notes covers all the exercise questions in SCERT Science Textbooks. The NCERT Class 9 Science MCQ Chapter 10 Gravitation provided here ensures a smooth and easy understanding of all the concepts. Understand the concepts behind every chapter and score well in the board exams.

Gravitation

Chapter – 10

### Multiple Choice Questions & Answers

1. The motion of earth around the sun is due to the

(a) gravitational force

(b) centripetal force

(c) collision force40

(d) Now of the above

Ans: (b) centripetal force.

2. Force of attraction between objects is called the –

(a) gravitational force

(b) attraction

(c) collision

(d) gravity

Ans: (a) gravitational force.

3. The value of G Universal law of gravitation is –

(a) 6.673×10¹¹NM²Kg⁻²

(b) 6.673×10¹°NM²Kg²

(c) 6.673×10⁻¹°NM²Kg⁻²

(d) 6.673×10⁻¹¹NM²Kg²

Ans (d) 6.673×10⁻¹¹NM²Kg⁻²

4. The mass of an object is 10kg. What is the weight of its on the earth?

(a) 9.8 N

(b) 980 N

(c) 98 N

(d) 9.8 N

Ans: (c) 98 N.

5. The weight of an object is 18N on the surface of the earth. What is the weight of its on the surface of the moon?

(a) 18 N

(b) 12 N

(c) 9 N

(d) 3 N

Ans: (d) 3 N.

6. The mass of an object is 18 N on the surface of moon. What is the mass of its on the surface of earth?

(a) 18 mg

(b) 12 mg

(c) 9 mg

(d) 3 mg

Ans: (a) 18 mg.

7. The value of g becomes greater at the poles than at the

(b) Africa

(c) USA

(d) equator

Ans: (d) Equator.

8. If m is the mass of the earth, and dis the distance between the object and the earth, then the gravitational force g is

M

(a) g = G+ ——

d²

M

(b) g = G ———

d²

M

(c) g = ——

Gd²

d²

(d) g = G ——

M

Ans:

M

(b) g = G ———

d²

weight of the object on the moon

9. ————————————————— = ……?

weight of the object on the earth

fill up the blank with appropriate fraction is the following –

(a) ⅓

(b) ¼

(c) ⅕

(d) ⅙

Ans: ⅙

10. The mass of an object on the earth is 5k. Them the mass of the object on the moon is –

(a) 5 kg

(b) 10kg

(c) 20kg

(d) 30kg

Ans: (a) 5kg.

11. Which of the following is correct

thrust

(a) pressure = ————

area

area

(b) pressure = ————

thurst

(c) pressure = thrust × area

(d) pressure = thrust + area

Ans:

thrust

(a) pressure = ————

area

12. What is the S. I. unit of pressure?

(a) Nm⁻¹

(b) Nm¹

(c) Nm⁻²

(d) Nm²

Ans: (c) Nm⁻²

13. The S. I. unit of density is –

(a) Kgm⁻²

(b) Kgm⁻³

(c) Kgm²

(d) Kgm³

Ans: (b) Kgm⁻³

14. The density of gold is –

(a) 19000Kgm⁻³

(b) 19100Kgm⁻³

(c) 19200Kgm⁻³

(d) 19300Kgm⁻³

Ans: (d) 19300K gm⁻³.

15. The density of water is

(a) 1000 Kgm³

(b) 1100Kgm⁻³

(c) 1200 Kgm⁻³

(d) 1300 Kgm⁻³

Ans: (a) 1000Kgm³.

16. Which of the following has no unit?

(a) density

(b) relative density

(c) pressure

(d) thrust

Ans: (b) relative density.

17. The relative density of silver is –

(a) 10.4

(b) 10.6

(c) 10.8

(d) 11.0

Ans: (c) 10.8.

18. The density of silver is –

(a) 108×10³Kgm⁻³

(b) 10.8×10³Kmg⁻³

(c) 1.08×10³Kgm⁻³

(d) 0.108×10³Kgm⁻³

Ans: (b) 10.8×10³Kmg⁻³

19. The value of acceleration due to gravity of the earth is

(a) 9.8 ms⁻²

(b) 9.8 ms⁻¹

(c) 98ms⁻²

(d) 98ms⁻¹

Ans: (a) 9.8 ms⁻²

20. The value of G (Universal gravitational constant) was found by

(a) Kepler

(b) Newton

(c) Henry cavendish

(d) Archimedes

Ans: (c) Henry cavendish.

21. According to Kepler, the orbit of a planet is an/a –

(a) parabola

(b) ellipse

(c) circular

(d) any of these

Ans: (b) ellipse.

22. The orbital velocity is v and the radius of the orbit is r. Then the force acting on an orbiting planet is given by –

v²

(a) F a ——

r

v²

(b) F = ——

r

v

(c) F ——

r

r

(d) v = ——

v

Ans:

v²

(a) F a ——

r

#### Very Short Answer Type Questions

1. What is called centripetal force?

Ans: The force which causes acceleration and keeps the body moving along the circular path is acting towards the centre. This force is called the centripetal force.

2. What is called tangent of a circle?

Ans: A straight line that meets the circle at only one point is called a tangent of a circle.

3. Give an example of centripetal force.

Ans: The motion of the moon around the earth is due to centripetal force.

4. What is called gravitational force?

Ans: All objects in the universe attract each others. This force of attraction between objects is called the gravitational force.

5. State the universal law of gravitation.

Ans: Every object in the universe attracts every other object with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them.

6. M and m are the mass of two objects and d is the distance between them and F is the force between them. What are the relation among them?

Mxm

Ans: F = G ———— [ G- constant ]

d²

7. Write the mathematical representation of universal law of gravitation.

Mxm

Ans: F = G ———

d²

8. What do you mean by universal gravitation constant?

Ans: The law of universal gravitation has a proportion constant. It is denoted by G. It is called universal gravitation constant.

9. What is the S. I. unit of the universal gravitation constant?

Ans: Nm²Kg⁻²

10. Write the value of universal gravitation constant.

Ans: G=6.673×10⁻¹¹Nm²Kg⁻²

11. Find the gravitational force (F), when the distance (d) of two objects 6 times increasing?

Ans: ¹/₃₆ times less.

12. What do you mean earth’s gravitational force?

Ans: An object falls towards the earth, an acceleration is involved. The acceleration is called the gravitation force of the earth or acceleration due to gravity.

13. What is the symbol of acceleration due to gravity?

Ans: g.

14. What is the S.I. unit acceleration due to gravity?

Ans: ms⁻²

15. What is the value of acceleration due to gravity?

Ans: 9.8ms⁻²

16. What is mass of earth?

Ans: 6×10²⁴kg.

17. What is the radius of earth?

Ans: R= 6.4 × 10⁶ m.

18. Acceleration due to gravity is g, universal gravitational constant G, the radius of earth R and mass of earth is M. What the relation among them?

GM

Ans: g = ———

R²

19. Write the difference between mass and weight.

Ans: The mass of an object is constant in any place. But weight depends on its location.

20. What is mass.

Ans: The mass of an object is the measure of inertia.

21. What is weight?

Ans: The product of mass and acceleration due to gravity is called weight.

22. The weight is W, mass is m and acceleration due to gravity is g. What is the relation among them?

Ans: W = mg

23. What is the S. I. unit of weight?

Ans: Newton.

24. The weight of an object is 6N on surface of earth. What is the weight of the object on surface of the moon?

Ans: IN.

25. The weight of an object is 2N on surface of the moon. What is the weight of the object on the surface of the earth?

Ans: 12 N.

26. What is weight of moon?

Ans: 7.36 × 10²² Kg.

27. What is the radius of moon?

Ans: 1.74 x 10⁶ m.

28. What is called thrust?

Ans: The force acting on an object perpendicular to the surface is called thrust.

29. What is called pressure?

Ans: The thrust on unit area is called pressure.

30. Write the mathematical expression of pressure.

thrust

Ans: Pressure = ———-—

area

31. What is the S. I. unit pressure?

Ans: Pascal.

32. What is the symbol of pascal?

Ans: Pa.

33. What is the value of 1 pascal?

1N

Ans: 1pascl = ———

1m²

34. What is called fluid?

Ans: All liquids and gases are fluid.

35. What is called Buoyancy force?

Ans: Upward force exerted by water is known as buoyancy force.

36. State the archimedes principle.

Ans: When a body is immersed fully or partially is a fluid, it experiences an upward force that is equal to the weight of fluid displaced by it.

37. What do you mean by ‘Eureka’?

Ans: Eureka means, I have got it.

38. Who discovered Pulley?

Ans: Archimedes.

39. Write an application of the Archimedes principle.

Ans: It is used in designing ships.

40. What is lactometer?

Ans: Lactometers are used to determine the purity of a sample of milk.

41. What is hydrometer?

Ans: Hydrometer used for determining the density of liquid.

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