Central Board Secondary Examination(CBSE) – Science Sample Paper (class 10)

Central Board Secondary Examination(CBSE) – Science Sample Paper
Set II

Time allowed: 2 hours 30 mins                                       Maximum Marks: 60

General Instructions:
1) The question paper comprises of two sections A and B. You are to attempt both sections.
2) All questions are compulsory.
3) There is no overall choice. However, internal choice has been provided in all the three questions of five marks category. Only one option in such questions is to be attempted.
4) All questions of section A and all questions of section B are to be attempted separately.
5) Questions 1 to 6 in section A and 17 to 19 in section B are short answer type questions. These carry one mark each.
6) Questions 7 to 10 in section A and 20 to 24 in section B are short answer types questions and carry two marks each.
7) Questions 11 to 14 in section A and 25 to 26 in section B are also short answer type questions and carry three marks each.
8) Questions 15 and 16 in section A and question 27 in section B are long answer type questions and carry five marks each.

SECTION A

1.  What happens when a small piece of sodium is dropped into ethanol?

2.  Which one of these has a higher concentration of H+ ions?

1M HCl or 1M

3. In electrolysis of water, why the volume of the gas collected over one electrode is double the volume of the gas collected over the other electrode?

4. State the rule which gives the direction of the magnetic field associated with a current-carrying conductor.

5. Define the term ‘induced current’.

6.  Draw a schematic diagram of an electric circuit consisting of a battery of two cells of 1.5 V each , three resistors  of 5 Ω, 10 Ω and 15 Ω respectively and a plug key, all connected in series.

7. Crystals of copper sulphate are heated in a test tube for some time.

(a) What is the colour of copper sulphate crystals

(i) before heating, and

(ii) after heating?

(b)What is the source of liquid droplets seen on the inner upper side of the test tube during the heating process?

8.  (i) What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube ?

(ii) what type of reaction is this?

(iii) write a balanced chemical equation to represent the above reaction?

9. A lamp rated 100 W at 220 V is connected to the mains electric supply. What current is drawn from the supply line if the voltage is 220 V?

10. What is an electric circuit? Distinguish between an open and a closed circuit.

11. (a) What is a homologous series of substances?

(b)In an organic compound, which parts largely determine its physical and chemical properties?

(c)Write a chemical equation to represent the reaction of ethanol   with acidified solution of potassium dichromate?

12. (a)What is meant by periodicity in properties of elements with reference to the periodic table?

(b)Why do all the elements of the same group have similar properties?

(c)How will the tendency to gain electrons change as we go from left to right in the periodic table?

13. (a)Define the term ‘coulomb’.

(b) State the relationship between the electric current, the charge moving through a conductor and the time of flow.

Calculate the charge passing through an electric bulb in 20 minutes if the value of current is 200 mA.

14. For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram.

15. (a)Distinguish between ionic and covalent compounds under the following properties:

(i) Strength of forces between constituent elements

(ii) Solubility of compounds in water

(iii)Electrical conduction in substances

(b)Explain how the following metals are obtained from their compounds by the reduction process:

(i) Metal M which is in the middle of the reactivity series

(ii)Metal N which is high up in the reactivity series

Give one example of each type.

16. (a) What is myopia? State the two causes of myopia. With the help of labelled ray diagrams show

(i) the eye defect myopia.

(ii) correction of myopia using a lens.

(b) Why is the normal eye unable to focus on an object placed within 10 cm from the eye?

 

 

Central Board Secondary Examination(CBSE) – Science Sample Paper
Set II

Time allowed: 2 hours 30 mins                                       Maximum Marks: 60

General Instructions:
1) The question paper comprises of two sections A and B. You are to attempt both sections.
2) All questions are compulsory.
3) There is no overall choice. However, internal choice has been provided in all the three questions of five marks category. Only one option in such questions is to be attempted.
4) All questions of section A and all questions of section B are to be attempted separately.
5) Questions 1 to 6 in section A and 17 to 19 in section B are short answer type questions. These carry one mark each.
6) Questions 7 to 10 in section A and 20 to 24 in section B are short answer types questions and carry two marks each.
7) Questions 11 to 14 in section A and 25 to 26 in section B are also short answer type questions and carry three marks each.
8) Questions 15 and 16 in section A and question 27 in section B are long answer type questions and carry five marks each.

SECTION B

17.  Why are green plants called ‘Producers’?

18. Why is DNA copying an essential part of the process of reproduction?

19. Which compounds are responsible for the depletion of ozone layer?

20. Describe how hydro – energy can convert into electrical energy. Write any two limitations of hydro – energy?

21. How is charcoal obtained from wood? Why charcoal is considered a better fuel than wood?

22. Describe the role of the following in human beings:

(i) Seminal vesicles

(ii) Prostate gland

23. An environmentalist on visit to your school suggested the use of three R’s to save the environment. Explain what he meant by three R’s and how you would follow his advice at home.

24. What is ‘Chipko Movement’? Why should we conserve forests?

25. Explain how the sex of the child is determined at the time of conception in human beings.

26. What is ‘hydrotropism’? Describe an experiment to demonstrate ‘hydrotropism’’?

27. (a) Draw a sectional view of the human heart and label on it Aorta, Pulmonary arteries, Vena cava, Left ventricle.

(b) Why is double circulation of blood necessary in human beings?

 

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