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Q1. N2 + 3H2 2NH3, name the type of reaction. (1) Q2. Why do we apply paint on iron articles' (1) Q3. Name the device which directly converts solar energy into electrical energy. (1) Q4. Name the instrument used to measure electric current in a circuit. (1) Q5. Explain why most of the metals do not displace hydrogen from Nitric acid. (2) Q6. What is bleaching powder' How is it prepared' State two uses of bleaching powder. (2) Q7. What is neutralization reaction' Give one example. (2) Q8. A white solid when dropped in water produces a hissing sound. What the solid may be' Give the chemical reaction for above observation. Name the product formed. (2) Q9. How are the fats digested in our bodies and where does this process take place' (2) Q10. Out of two solar cookers one was covered by a plane glass slab and other was left open, which of two solar cookers will be more efficient and why. (2) Q11. What is the (a) highest (b) lowest resistance that can be secured by combining four coils of resistance 4, 8, 12and 24. (2) Q12. What s meant by the term magnetic field lines' List any two properties of magnetic field lines. (2) Q13. An electric bulb draws a current of 0.8A and works on 250V on the average 8 hours a day, if energy costs Rs 3 per kWh. Calculate monthly bill for 30 days. (2) Q14. Take 2g silver chloride in a china dish and place it in sunlight: (a) Observe the colour of silver chloride after some time (b) What type of reaction takes place' (c) Write the chemical reaction for above observation. (3) Q15. What is plaster of paris' How is it prepared' State two important uses of plaster of paris. (3) Q16. Tooth enamel is one of the hardest substances in our body. How does it undergo damage due to the eating of chocolates and sweets' What should we do to prevent it' (3) Q17. What is reflex arc' Draw diagram of reflex arc. What is the role of the brain in reflex action' (3) Q18. What are the different ways in which glucose is oxidised to provide energy in various organisms' (3) Q19. What is biomass' Draw schematic diagram of biogas plant. What are the constituents of biogas' (3) Q20. (3) In above circuit diagram calculate: (a) the value of current through each resister (b) the total current in the circuit (c) the total effective resistance of circuit. Q21. (a) What is meant by electric resistance of conductor' (3) (b) A wire of length L and resistance R is stretched so that the length is doubled and area of cross section halved. How will (i) resistance change and (ii) resistivity change. Q22. Express joules law of heating mathematically. What is the resistance of 12m wire having radius 2x10-4m. Specific resistivity is 3.14x10-8m. (3) Q23. (a) Describe the steps associated with extraction of copper from its sulphide ore. (b) How impure copper is purified by electrolytic refining. (5) OR (a) Write the electron dot structures of sodium, oxygen and magnesium. (b) Show the formation of Na2O and MgO by transfer of electrons. (c) Give three properties of ionic compounds. Q24. (a) Draw neat labelled diagram of human brain (b) What is the function of mid brain. (c) Name the three different parts of hind brain and give on function of each. (5) OR (a) Name two hormones secreted by pancreas. Write one function of each hormone. (b) How does our body respond when adrenaline is secreted into the blood' (c) Site an example to explain feedback mechanism for regulation of hormonal secretion. Q25. (a) What is the function of earth wire in electrical instruments' Why is it necessary to earth the metallic electric appliances' (b) Explain what is short circuiting and overloading in an electric supply. (5) OR (a) State Fleming’s left hand rule with a labelled diagram. (b) A coil of insulated copper wire is connected to a galvanometer. What happens if a bar magnet is (i) pushed into the coil (ii) withdrawn from inside the coil (iii) held stationary inside the coil SECTION-B Q26. Bottle A contains a dilute solution of vinegar and bottle B contains sodium carbonate solution the colour seen in pH paper dipped in A and B are (1) (a) Orange, blue (b) Green, blue (c) Blue, orange (d) Orange, green Q27. A student took the following samples to find out their pH using pH paper. The teacher remarked that one of the samples taken was not proper. The teacher was referring to: (1) (a) Dilute hydrochloric acid (b) Washing soda (c) Soap solution (d) Distilled water Q28. When a student added zinc granules to dilute HCl, a colourless and odourless gas evolved on testing with a burning match stick. It was observed that: (a) The matchstick continued to burn brilliantly. (b) The matchstick burnt slowly with a blue flame. (c) The matchstick extinguished and gas burned with pop sound. (d) The matchstick continued to burn brilliantly and gas burnt with pop sound. (1) Q29. Copper turnings were added to a colourless salt solution. After 10 minutes, it was observed that the colourless solution turned to a coloured solution and shiny metal deposition appears. The colour of the solution and that of metal would respectively be: (1) (a) Yellow and Zn (b) Green and Fe (c) Red and Sn (d) Blue and Ag Q30. Four students performed reactions of Zinc and Sodium carbonate with dilute hydrochloric acid and dilute sodium hydroxide solutions and presented their results as follows. The ( ) represents evolution of gas and (x) represent no reaction. (1) The right set of observation is that of student: (a) A (b) B (c) C (d) D Q31. The resistors R1 and R2 are connected in (1) (a) Parallel in both circuits (b) Series in both circuits (c) Parallel in circuit I and in series in circuit II (d) Series in circuit I and in parallel in circuit II Q32. The correct way of connecting the ammeter and voltmeter with a series combination of two resistors in a circuit for finding their equivalent resistance in shown in diagram: (1) (a) A (b) B (c) C (d) D Q33. Which two circuit components are connected in parallel in the following circuit diagram' (1) (a) Rheostat and voltmeter (b) Voltmeter and resistor (c) Voltmeter and ammeter (d) Ammeter and resistor. Q34. A student has to connect 4 cells of 1.5 V each to form a battery of voltage 6V. Which connection is correct' (1) (a) A (b) B (c) C (d) D Q35. On plugging the key the voltmeter/ammeter is likely to be damaged in the circuit shown in figure: (1) (a) A (b) B (c) C (d) D Q36. In the following sketch of the stomatal apparatus the parts I, II, III, IV were labelled differently by four student: (1) The correct labeling out of the following is: (a) (I) guard cell, (II) Stoma, (III) Starch granule, (IV) Nucleus (b) (I) cytoplasm, (II) Nucleus (III) Stoma, (IV) Chloroplast (c) (I) Guard Cell, (II) Starch granule, (III) Nucleus (IV) Stoma (d) (I) Cytoplasm, (II) Chloroplast, (III) Stoma, (IV) Nucleus Q37. A leaf from a destarched plant is covered with black paper strip as shown in figure .1. The starch test is done on the leaf after 8 hours. (1) The results will be as shown in diagram (a) A (b) B (c) C (d) D Q38. In the experiment shown in the figure, water is found to rise in the bent tube: The reason is that (a) seeds use up oxygen in the flask (b) carbon dioxide is given out by germinating seeds (c) germinating seeds attract water from the beaker (d) seeds use oxygen and release CO2 which is absorbed by potassium hydroxide due to which a partial vacumn is created. (1) Q39. The teacher instructed a student to place a healthy potted shoe flower plant in a dark room for 24 hours prior to an experiment on photosynthesis. The purpose of placing it in a dark room is (a) to increase the intake of CO2 (b) to activate the chloroplasts in the leaves (c) to destarch the leaves (d) to denature the enzymes in the leaves (1) Q40. A student performed to starch test on a leaf. Some steps involved are shown below: (1) The correct sequence of steps should be (a) (iv), (iii), (ii), (i) (b) (i), (ii), (iii), (iv) (c) (ii), (iii), (iv), (i) (d) (i), (iii), (iv), (ii) Q41. The stain used to see the stomata during temporary mount of leaf peel is: (1) (a) Safranin (b) Methylene blue (c) Cotton Blue (d) Acetocarmine