CBSE Class 10 Science Question Paper SA 1 2011 (7)

CBSE Class 10 Science Question Paper SA 1 2011 (7). Students can download the last year question papers using the link below. Free download of examination question papers with solutions. Last 10 year question papers should be practised to get better marks in examinations.

SUMMATIVE ASSESSMENT - I (2011)

SCIENCE  Class – X

SECTION-A

1. A few drops of sulphuric acid are added into water before electrolysis. Why ?

2. Give an example of a metal which is a liquid at room temperature.

3. Give one limitation of harnessing energy from Geothermal sources.

4. The resistance of a resistor is kept constant and the potential difference across its two ends is decreased to half of its former value. State the change that will occur in the current through it.

5. What is an alloy ? Give the composition and one use each of the following : (i) Brass (ii) Solder

6. Name the product obtained by recrystallisation of sodium carbonate and write its chemical formula.

7.   (a) A solution of substance ‘X’ is used for white washing. What is the substance ‘X’ ? State the chemical reaction of ‘X’ with water.

      (b) Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?

8. Stomata of desert plants remain closed during day time. How do they take up carbon dioxide and perform photosynthesis ?

9. What is meant by ‘ocean thermal energy’ ? How can electricity be generated from the ocean energy ?

10. An electric resistor of resistance 20Ω draws a current of 5A. Calculate the heat produced by it in 30 seconds.

11. A student while studying the force experienced by a current carrying conductor in a magnetic field, records the following observations :

      (i) The force experienced by the conductor increases as the current is increased

      (ii) The force experienced by the conductor decreases as the strength of the magnetic field is increased.

12. A thick wire and a thin wire made from same material and of same length are connected one by one to the same source. In which case a larger current will flow in the circuit ? Justify your answer.

13.  (a) What is a decomposition reaction ?

      (b) What type of reaction will occur when silver chloride is exposed to sun light ?

      (c) Identify the type of the reaction, when lead (II) nitrate solution is mixed with potassium iodide solution.

14. (a) How is common salt prepared from sea water?

      (b) What will be the approximate pH of the aqueous solutions of the following salts :

      (i) Sodium chloride (ii) Ammonium Chloride

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