I have consolidated the question from previous years question papers for CBSE 9th Science -Physics

Chapter: Gravitation

Topic :Buoyancy

1. Define relative density. What is the density of Silver given its relative density is 10.3?(2)
2. (2016-17 SAII)(2+1 marks)

               (a)  Acceleration due to gravity of a person on a planet A is half of that on Earth. He can jump up to a height 

                     of 0.4 m on the surface of the Earth. How high can he jump on planet A when his potential energy

                      remains same on both the planets(2)

               (b) Find the velocity of a body of mass 100g having a kinetic energy of 20J(1)

3. (2015-16 SAII )(3 marks)

                 Define relative density. The density of water is 10³kg/m³. Relative density of iron is 7.8. What is the  

                 density   of iron in SI unit?                               

4. (2015-16 SAII )(3 marks)

            (a) A dining hall has dimensions 50mX15mX3.5m .Calculate the mass of air in the hall. Density of air=1.3  

                  kg/m³

          (b) State unit of Relative density

5. (5 marks)

                  State Archimedes principle

       Explain giving reason the following.

1. It is easier to swim in sea water that river water.
2. A nail can be easily fixed on a wall by putting its pointed edge on it.
3. It is difficult to cut a fruit with blunt knife

6. State Archimedes Principle. State two of its application (2 marks) (2016-17 SAII)

7. (3 marks)( (2016-17 SAII)

• Why is it easier to walk on soft sand with flat shoe than a pencil heeled shoe?
• While drawing water from the well, the bucket of water appears to be heavier as it comes out of water. Why?
• A 100cm³ block has a mass of 395g. Find its relative density. (Density of water=1g/cm³)

8. (3 marks)(2015-16 SAII)

• Explain why a completely immersed closed empty bottle in water when released , bounces back on the surface.
• Why does bucket of water weighs less inside the well water.

9. (3 marks) (2015-16 SAII)

• What is upthrust?
• Write application of (1) Lactometer (2) Hydrometer

10. (3 marks) (2015-16 SAII)

A Goldsmith measured the purity of the gold by using a special measuring device. He told the customer that there was impurity present in gold ornament that he wanted to buy and was not of twenty two carats but instead 18 carat

• How can we find purity of gold?
• What is the unit of relative density?
• Why did the goldsmith disclose impurity in the gold ornament?

11.(2 marks) (2015-16 SAII)

In the experiment of finding volume of a solid by immersing it into water, the initial reading of water level graduated cylinder was 16.2 ml. On immersing the given solid completely into water, the water level in graduated cylinder rose to 19.7 mL. Find the volume of the solid

12.(2 marks) (2015-16 SAII)

A student noted down the weight of an object in air , tap water and salty water , as 70gm wt, 60gm wt and 65 gm wt respectively. Are his observations correct? Explain.

13.(5 marks)(2015-16 SAII)

• An army tank weighing more than a hundred ton can move easily on even earthen road. Why? Explain
• State Archimedes principle and write any three applications of Archimedes principle.

14. (2 marks)(2015-16 SAII)

In an experiment to find density why the measuring cylinder with less least count is preferred? When solid block is fully immersed in water, how much will be the apparent loss in weight of the block?

15.(2 marks)(2015-16 SAII)

State two factors on which buoyant force acting on an object immersed in fluid depends?

16.(3 marks)(2015-16 SAII)

A milkman used to sell milk in the city and always carried lactometer with him. The customers trusted him and his business flourished

• What is a lactometer?
• What is the principle of working of lactometer?
• Carrying a lactometer by milkman shows his high values. List any two.

17. (2 marks)(2015-16 SAII)

If two balls made of iron and aluminum of equal volumes are immersed in a liquid, then will they experience equal up- thrust? Justify your answer.

18.(2 marks)(2015-16 SAII)

A student uses a spring balance of least count 10gm and range 500 gm. He records the weight of a small lead sphere in air, in tap water and in a concentrated solution of salt water respectively .If the reading are in order w1,w2 and w3. Write relation between them with reason.

19.(5 marks)(2014-15 SAII)

Define relative density. Give its mathematical formula.

Define density. Give its SI unit.

A solid weighs 80 gm in air, 64 gm in water. Calculate the relative density of solid.

When kept in water, state if the object would float or sink?

20.(2 marks)(2014-15 SAII)

You are given a sphere of radius 2 cm. If you are asked to select a best suited spring balance to determine its weight, then what should be the range and least count of the spring balance?

(The sphere is made of an alloy of density 7X 10³kgm^-3)

21.(2 marks)(2014-15 SAII)

If we want to determine the volume of a solid by immersing it in water, what kind of solid should we choose? Write its features

22.(3 marks)(2013-14 SAII)

State Archimedes Principle. What are its application?

Why does a block of plastic released under water come up to the surface of water.

23.(3 marks)(2013-14 SAII)

• Define buoyancy
• A solid body of mass 150g occupies 60 cm³ Will the solid sink of float? Given density of water is 1g cm^-3

24.(2 marks)(2013-14 SAII)

Measuring cylinders and spring balance shown here

1. 5 ml 10gt
2. 5 ml 2 gt
3. 1 ml 10gt
4. 1 ml 2gt

 

 

25.(2 marks)(2013-14 SAII)

 A block of ice floats in water such that the temperature of water as well as is 0⁰ C. In this situation, the weight of ice is equal to the:

• Weight of water displaced by immersed part of ice
• Volume of water displaced by the immersed part of ice
• Weight of water displaced by the complete block of  ice
• None of these