CBSE Board Class 10 Science Previous Year Question Papers 2011

Previous Paper 2011
Class 10 
Science

1. Classify the following reactions into slow and fast reaction :
(i) Reaction between an acid and a base,
(ii) Rusting of iron. 1

2. Give the names of the functional groups
(i) — CHO
      |
(ii)    — C=O 1
(i) — CHO
      |
(ii)    — C=O
3. What is a Galaxy ? 1

4. What is the S.I. unit of electric potential ? 1

5. (a) Give Arrhenius definition of an acid and a base.
(b) Choose strong acid and strong base from the following :
CH3
COOH, NH 4
OH, KOH, HC l. 2

6. What is Tollen’s reagent ? What would you observe on heating Tollen’s reagent with
formalin in a test tube ? 2

7. Distinguish between polar and equatorial orbits for artificial satellites. Illustrate the
two orbits on a diagram. 2

8. An electric iron has a rating of 750 W, 220 V. Calculate
(i) current passing through it, and
(ii) its resistance, when in use. 2

9. (Name the raw materials that are required for the manufacture of washing soda by
Solvay Process. Describe the chemical reactions involved in the process. 3

10. What is ‘liquor ammonia’ ? Describe with a diagram, ‘Fountain Experiment’ to
demonstrate the following properties of ammonia :
(i) high solubility in water.
(ii) its alkaline nature. 3

11. Give reasons for the following :
(i) A  peculiar  smell  is  observed  near the  preserved  specimens  in biology laboratory.
(ii) Methanal undergoes addition reaction with hydrogen cyanide,
(iii) Propanone can be used as a nail polish remover. 3

12. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall
object be placed so that it forms an image at 15 cm from the lens ? Also calculate the
size of the image formed. 3

13. (a) Why is the Solar Cooker box covered with a plane glass plate ?
(b) Why is energy of water flowing in a river considered to be an indirect form of
Solar energy ?
(c) How is the fission of 
nucleus brought about ? 3

14. (a)    What is meant by ‘Electric Resistance’ of a conductor ?
(b) A wire of length L and resistance R is stretched so that its length is doubled and
the area of cross-section is halved. How will its :
(i) resistance change ?
(ii) resistivity change ? 3

15. (a) Name one main ore of Aluminium. Write its formula. Which two main impurities
are associated with this ore ?
(b) Describe with chemical equations, the method employed for the enrichment of the above
named ore.
OR
(a) Why is sulphuric acid called ‘King of Chemicals’ ?
(b) Describe the three chemical reactions that take place during the conversion of
sulphur dioxide to sulphuric acid in the ‘Contact Process’.
(c)     Why should water be never added dropwise to concentrated sulphuric acid ? 5

16. Define the term, ‘Critical Angle’. What is meant by ‘total internal reflection’ ? State two
essential conditions for total internal reflection to take place. With the help of a ray
diagram, illustrate an application of total internal reflection.
OR
(a) What is meant by a ‘magnetic field’ ?
(b) How is the direction of magnetic field at a point determined ?
(c) Describe  an  activity to  demonstrate the  direction of the magnetic  field generated
around a current carrying conductor.
(d) What is the direction of magnetic field at the centre of a current carrying circular

SECTION  B
17. Name the term for transport of food from leaves to other parts of the plant. 1

18. What is a neuron ? 1

19. Describe the mechanism of blood clotting. 2
                        OR
State the two vital functions of the human kidney. Name the procedure used in the working
of  artificial  kidney. 2
        
20. Name the two hormones secreted by pancreas. Write one function of each hormone
named. 2

21. (a) What is fertilization ? Distinguish between external fertilization and internal fertilization.
(b) What is the site of fertilization in human beings ? 3

22. Define the terms :
(i) Analogous organs
(ii) Vestigial organ
(iii) Sex chromosome 3

23. (a) What is ‘environmental pollution’ ?
(b) Distinguish between biodegradable and non-biodegradable pollutants.
(c) Choose the biodegradable pollutants from the list given below :
Sewage, DDT, radioactive waste, agricultural waste.
OR
Suggest three ways to maintain a balance between environment and development to
survive. 3

24. (a) Draw a diagram of a ‘palisade cell’.
(b) Label vacuole, chloroplast, cell wall and cytoplasm on the diagram drawn.
(c) Name the two stages in photosynthesis.