SAMPLE QUESTION PAPER II
X - SCIENCE (Theory)

Time : 2½ Hours Max.
Marks : 60

General Instructions :
1. The question paper comprises of two sections A and B. You are to attempt both the 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 questions. These carry one mark each.
6. Questions 7 to 10 in section A and 20 to 24 in section B are short answer type 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. A ray of light AM is incident on a spherical mirror as shown in the diagram. Redraw the diagram on the answer sheet and show the path of reflected ray. Also indicate and mark the angle of reflection in the diagram.

2. A metal M forms an oxide having the formula M2 O3. It belongs to 3rd period in the modern periodic table. Write the atomic number and valency of the metal.

3. The ciliary muscles of a normal eye are in their (i) most relaxed (ii) most contracted state. In which of the two cases is the focal length of the eye-lens more?

4. Tap water conducts electricity whereas distilled water does not. Why?

5. An electric geyser has the ratings 2000W, 220V marked on it. What should be the minimum rating, in whole number of a fuse wire, that may be required for safe use with this geyser?

6. An organic compound burns with a sooty flame. Is it a saturated or an un saturated compound?

7. Two metallic wires A and B are connected in parallel. Wire A has length l and radius r, wire B has a length 2l and radius 2r. Compute the ratio of the total resistance of parallel combination and the resistance of wire A.

8. A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor. He reports that (i) the direction of deflection of the north pole of a compass needle kept at a given point near the conductor remains unaffected even when the terminals of the battery sending current in the wire are inter changed. (ii) for a given battery, the degree of deflection of a N-pole decreases when the compass is kept at a point farther away from the conductor. Which of the above observations of the student is incorrect and why?

9. A housewife wanted her house to be whitewashed. She bought 10kg of quick lime from the market and dissolved it in 30 litres of water. On adding lime to water she noticed that the water started boiling even when it was not being heated. Give reason for her observation. Write the corresponding chemical equation and name the product formed.

10. Write the electron - dot structure for sodium and chlorine atoms. How do these form a chemical bond? Name the type of bond so formed. Why does a compond so formed have high melting point?

11. Two carbon compounds A and B have the molecular formula C3 H8 and C3 H6 respectively. Which one of the two is most likely to show addition reaction? Justify your answer. Explain with the help of a chemical equation, how an addition reaction is useful in vegetable ghee industry.

12. A beam of white light falling on a glass prism gets split up into seven colours marked 1 to 7 as shown in the diagram. A student makes the following statements about the spectrum observed on the screen.
a) The colours at positions marked 3 and 5 are similar to the colour of the sky and the core of a hard boiled egg respectively.  Is the above statement made by the student correct or incorrect? Justify.
b) Which two positions correspond closely to the colour of  (i) a solution of potassium permanganate? (ii) ‘danger’ or stop signal lights?

13. Baking soda is used in small amount in making bread and cake. It helps to make these soft and spongy. An aqueous solution of baking soda turns red litmus blue. It is also used in soda acid fire extinguisher.
Use this information to answer the following questions:
(i) How does Baking Soda help to make cakes and bread soft and spongy?
(ii) How does it help in extinguishing fire?
(iii) is the pH value of baking soda solution lesser than or greater than 7?

14. A concave mirror produces three times enlarged image of an object placed at 10 cm infront of it. Calculate the radius of curvature of the mirror.

15. a) What were the two major shortcomings of Mendeleev’s periodic table? How have these been removed in the modern periodic table? b) Two elements X and Y have atomic numbers 12 and 16 respectively. Write the electronic configuration for these elements. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why?

OR

a) What were the two achievements of Mendeleev’s Periodic table? What was the basis of classification of elements in it ? b) An element X (2,8,2) combines separately with NO3 and (SO4)2 -, (PO4)3 - radicals. Write the formulae of the three compounds so formed. To which group of the periodic table does the element ‘X’ belong? Will it form covalent or ionic compound? Why?

16. a) The electric power consumed by a device may be calculated by using either of the two expressions P = I2R or P = V 2. The first expression indicates that it is directly R proportional to R whereas the second expression indicates inverse proportionality.

How can the seemingly different dependence of P on R in these expressions be explained?

b) Explain the following:
(i) Why is tungsten used almost exclusively for filament of electric lamps?
(ii) Why are copper and aluminium wires usually used for electricity transmission?

OR

Explain the meaning of the word ‘electromagnetic’ and ‘induction’ in the term electromagnetic induction. On what factors does the value of induced current produced in a circuit depend? Name and state the rule used for determination of direction of induced current. State one practical application of this phenomenon in everyday life.

SECTION - B
17. From the list given below, pick out the items which can be recycled:-
Used clothes, polythene carry bags, glass bottles, newspaper 1

18. What does the given experimental set-up domonstrate? 1

19. A particular hormone requires lodine for its synthesis. Name the endocrine gland which secretes this hormone and state its location in the human body. 1

20. Why are many thermal power plants set up near coal or oilfields? 2

21. Name those parts of the flower which serve the same function as the following do in the animals:-
(i) testis (ii) ovary (iii) eggs (iv) sperms

22. A graph was plotted to show the energy output of two types of respiration. Identify the types of respiration denoted by curves A and B. 2

23. How did the ‘Chipko andolan’ ultimately benefit the local population? Give any two benefits. 2

24.
(i) Label the two parts indicated by question marks and labelled 1 and 2 in the above diagram.
(ii) Suggest a suitable caption or heading for the above diagram. 2

25. Write the number given to any six of the organisms shown in Figure B against their relevent Trophic levels given in figure given below. 3

26. The genotype of green stemmed tomato plants is denoted as GG and that of purplestemmed tomato plants as gg. When these two are crossed,
(i) What colour of stem would you expect in their F1 progeny?
(ii) Give the percentage of purple-stemmed plants if F1 plants are self pollinated.
(iii) In what ratio would you find the genotypes GG and Gg in the F2 progeny? 3

27. (i) Draw the diagram of heart and label its four chambers (ii) Construct a table to show the functions of these four chambers. 5

OR

Plants absorb water from the soil. How does this water reach the tree tops? Explain in detail .