Tuesday, September 20, 2011

Sample Papers & Study Materials for Class X

10th Science Guess Question Paper 2011-12
Class – X                           Time: 3 Hr.                                    M.M: 55marks

 (Questions number 1 to 4 carry one mark each)
1. In the reefing of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write the reaction involved.
2. The electrolysis of an aqueous solution of sodium chloride gives us three products. Name them.
3. What name given to the heat energy obtained from hot rocks inside the earth?
4. What happens to the resistance as the conductor is made thinner?
Questions number 5 to 13 carry two marks each)
5. How is the sodium metal extracted? Explain with the help of equation of the reaction involved.
6. How does baking powder differ from baking soda?
7. A colorless lead salt, when heated produce a yellow residue and brown fumes. Identify the yellow residue and brown fumes.
8. Why does color of copper sulphate solution change when iron nails kept immersed in it?
9. “Structure of small intestine is suited to its function”. Justify.
10. What is the difference between a thermal power plant and a hydropower plant?
11. An electric heater draws a current of 10A from a 220V supply. What is cost of using the heater for everyday for 30 days if the cost of one unit is Rs. 5.20?
12. Explain why, a copper wire cannot be used as a fuse wire?
13. (a)State and explain Joule’s law of heating. (b)Explain why argon and nitrogen is filled in an electric bulb?
(Questions number 14 to 22 carry three marks each)
14. When a green salt is heated strongly s strongly, it color finally change to black and odour of burning sulphur is given out
(a) Name the iron salt. 
(b) Name the type of reaction that takes place during the heating of iron salt.
(c) Write a chemical reaction for the reaction involved.
15. Explain the pH change as the tooth decay. How can tooth decay caused by pH change be prevented?
16. (a) Why does an aqueous solution of acid conduct electricity? (b) What happens during nettle leaves sting?
17. (a) What is the role of the brain in reflex action? 
 (b) What is Nastic movement? (c) What is synapse?
18. (a) How do auxins promote the growth of tendril around support 
 (b) Name the plant hormone that inhabits the growth of plants
19. (a) What is meant by ocean thermal energy? 
 (b) Why is bio- gas considered an ideal fuel for domestic use?
20. How you can three resisters of 2 ohm, 3 ohm, and 5 ohm respectively so as to obtain a resultant resistance of 2.5 ohm? Draw the diagram to show the arrangement. (b) Define potential difference.
21. A copper wire has a diameter of 0.5mm and resistivity of 1.6 ohm meter
(a) What will be the length of this wire to make its resistance 10 ohm?
(b)How much does the resistance change if the diameter is doubled?
22. (a)Why are copper and aluminum wires usually used for electricity transmission
(b)Define resistivity. Write its S.I.
(Questions number 23 to 25 carry five marks each)
23. (a) Give reason; platinum, gold and silver are used to make jewelry (b) What are the amphoteric oxides? Give its two examples
(c) In the electrolytic refining of a metal M”, what would you take as the anode, the cathode and the electrolyte?                                             OR,
 Explain how the following metals are obtained from their compounds by the
(a) Metal “M” which is high up in the reactivity series.
(b) Metal “X” which is in the middle of the reactivity series Give one example of each.
24. (a) How are the alveoli designed to maximize the exchange of gases?
(b) Why do herbivores have longer intestine?
(c) What are the end products of digestion?
(d) What is the main function of bile?
(e) On which molecule does life on earth depend?  
(a) Give a schematic representation of transport and exchange of oxygen and carbon- dioxide 
in human beings.
(b)How is it beneficial to have large number of highly coiled nephrons in our kidneys?
25. (a) What is the electromagnet? Draw a circuit diagram to show a soft iron piece can be transformed into an electromagnet?
(b) What is the purpose of soft iron core is used in making an electromagnet?
(a) Describe the pattern of magnetic field of a straight current carrying conductor.
(b) How will you determine the direction of a magnetic filed around a straight current carrying conductor?

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