** Class 9 Science MCQ Chapter 10 Gravitation**,

**,**

**Class 9 Science MCQ Question Answer****to each chapter is provided in the list of**

**Class 9 Science Multiple Choice Question Answer****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**

**can be of great value to excel in the examination.**

**Question Answer****10 Gravitation**## 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**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.

**10 Gravitation****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**

**(a) Canada **

**(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.