SCIENCE & TECHNOLOGY

CLASS X (THEORY)

Sample Question Paper III

TIME : 2 ½ 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. The candidates are advised to attempt all the questions of Section A separately and section B separately.
3. All questions are compulsory.
4. There is no overall choice. However, internal choice has been provided in two questions of five marks category in Section A and one question of 2 marks category and one question of 3 marks category in section B. You are to attempt only one option in such questions.
5. Marks allocated to each question are indicated against it.
6. Questions 1 to 4 in Section A and 17, 18 in Section B are very short answer questions. These are to be answered in one word or one sentence only.
7. Questions 5 to 8 in Section A and 19, 20 in Section B are short answer questions. These are to be answered in about 30-40 words each.
8. Questions 9 to 14 in Section A and 21 to 23 in Section B are also short answer questions. These are to be answered in about 40 – 50 words each.
9. Questions 15, 16 in Section A and 24 in Section B are long answer questions. These are to be answered in about 70 words each.

SECTION A

1. A ray of light incident obliquely on the surface of a rectangular glass slab emerges out of the opposite face undergoing some lateral displacement. How will the lateral displacement produced by the slab change on increasing the thickness of the slab ? (1)
2. A student connects the electroplating apparatus, in turn, to a 6V i) alternating current source ii) direct current source In which of the two cases will electroplating take place ? (1)
3. Photo chromatic glasses darken on exposure to light. Name the compound present in glass responsible for this property. (1)
4. Why does a building made of marble start getting damaged with time in an area having factories that use fossil fuels? (1)
5. Consider a chemical reaction between given amount of Zinc and 1M HCl. Let this reaction be carried out, in turn, at 300 K and 310 K. Draw graphs showing variation in volume of hydrogen gas evolved with time in two cases. (2)
6. What is an optical fiber? State the property on which it works. Write its one use. (2)
7. Why is electromagnetic induction so called ? A coil connected to a sensitive galvanometer is held stationary. A bar magnet with its north pole facing coil is moved towards the coil at a certain speed. The galvanometer needle shows deflection of 10 divisions towards right of the centre of scale. How will the reading on the galvanometer scale be affected if the south pole of the bar magnet facing the coil is moved away at the same speed ? (2)
8. Two resistors with reisistances 10 Ohm and 15 Ohm are to be connected to a battery of emf 5V so as to obtain i) maximum current ii) minimum current. a) How will you connect the resistances in each case? b) Calculate the strength of total current in the circuit in the two cases. (2)
9. Complete the following chemical reactions

i) CH3 COOH + CO

ii) CH3 CO CH3

iii) CH3 CH2 OH (3)
10. A thin converging lens forms a

i) real image

ii) virtual image of an object placed in front of it. The size of the image is three times the size of the object in each case. Draw labeled ray diagrams to show the image formation in each case. How will the focal length of such a lens be affected on cutting it into two equal halves along the principal axis ? (3)
11. Examine carefully the following diagrams of experimental set up of the apparatus labeled as A, B and C. In which of the three cases corrosion occurs? Justify your answer. (3)
12. Explain the following :

i) The element of electric heating devices is made of an alloy rather than a pure metal.

ii) Tungsten is almost exclusively used for making filament of incandescent lamps.

iii) Parallel electric circuit arrangement is used for domestic wiring. (3)
13. A metal occurs in nature in its sulphide form. Explain, with a labeled diagram, the process used to enrich this ore. State the principle on which this process works. (3)
14. What are two special characteristic properties of the fuels used for launching rockets? Why are liquid fuels considered risky for launching the rockets? Why do we require multi-stage rockets for satellites carrying pay loads ? (3)
15. Name the chief ore of iron. How is it concentrated? Draw a labeled diagram of Blast furnace for extraction of iron. Write balanced chemical equations for the reactions taking place in blast furnace. (5)

OR

a) Draw a labeled diagram for Frasch process used for extraction of sulphur.

b) Describe an activity to observe the changes through which sulphur undergoes when melted.
16. In a nuclear reaction, a heavy nucleus disintegrates into two lighter nuclear fragments with release of energy. Name this nuclear process. Give an example of such a nuclear reaction. Suggest one peaceful application of this process. Give one advantage and one disadvantage of use of this process for conversion of nuclear energy into electrical energy. (5)

OR

In a nuclear reaction, two lighter nuclei combine to form a comparatively heavier nucleus with release of energy. Name this nuclear process. Give an example of such a nuclear reaction. State two advantages of this process for conversion of nuclear energy to electrical energy. Why is it difficult to use such a process for commercial generation of energy ?

SECTION – B

17. What is the function of pancreas in the human digestive system? (1)
18. What disadvantage, if any, would be there if the human RBCs become biconvex instead of their normal biconcave shape ? (1)
19. Distinguish between homologous and analogous organs. To which of these categories the spine of cactus and thorn of Bougainvillea belong and why? (2) OR Where are genes located ? What is the chemical nature of genes ?
20. Why are endocrine glands called ductless glands? Give two characteristics of their secretions. (2)
21. What is blood clotting ? With the help of a flow chart show the major events in blood coagulation. (3)
22. What is entrophication? Describe the modern technique of treating sewage before it is discharged into the river. (3)
23. Draw a diagram representing nervous system of an insect and label brain, ganglion and nerve cord in it. (3)

OR

Draw a diagram of human respiratory system and label larynx, trachea, primary bronchus and lungs in it.
24. What is vegetative propagation? Describe three methods of artificial vegetative propagation. List two advantages of vegetative propagation. (5)

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