CBSE Board Class 10 Science Previous Year Question Papers 2008


CBSE Board Previous Year Question Papers 2008 for Class 10 Science

Sample Paper – 2012
Class – X
Subject – Physics
Marks: 75          
     
General Instructions:

(i) All questions are compulsory.
(ii) Question No. 1 to 3 in section A are very short answer type questions carrying one mark each. The questions are to be answered in one word or a sentence.
(iii)  Question No. 4 to 6 in section A are short answer type questions carrying two marks each. Their answers may not normally exceed 40 words each.
(iv) Question No. 7 and 8 in section A are also short answer type questions carrying three marks each. Their answers may not normally exceed 60 words each.
(v)  Question No. 9 in section A is long answer type question carrying five marks
(vi) Questions number 10 to 14 in Section B are multiple choice questions based on practical skills. Each

question is a one mark question. You are to select one most appropriate response out of the four provided to you.

SECTION A

1.For what position of an object, a concave mirror forms an enlarged virtual image?

2.An object is placed in front of a mirror,  image of this object is formed  on a screen placed 50 cm from the mirror ,if height of the image is two times the object, calculate the object distance.

3.Name the defect of vision in a person whose near point is more than 25 cm away.

4.Give reason for the following.

(i) Red colour is used in Danger signals.
(ii) Sun and its surrounding sky appear red.

5. Write lens formula. Use lens formula to find the distance ‘x’ in the given diagram. 

6.Name the Mirrors used for the following

(i) Used as shaving Mirror.
(ii) Used as reflectors in street lights.
(iii) Used by dentist .
(iv)  Reflectors of head lights in cars.

7.(i) Give any 3 properties of the image formed on the mirror.

8.Explain the function of the following parts in human eye.

(i)  Retina  
(ii) Pupil
(v)  Ciliary muscles

9.The following diagram shows a defect of eye .

(i)  Identify the defect
(ii) What are its causes?
(iii) Draw a diagram showing its correction?
(iv) Name the type of lens used for its correction.

Section B

10.The diagram shows the dispersion of white light by a glass prism. Why does dispersion occur when white light enters the glass?

(A)The frequency of red light decreases more than that of violet light.
(B) The frequency of violet light decreases more than that of red light.
(C) The speed of red light decreases more than that of violet light.
(D) The speed of violet light decreases more than that of red light.

11. Balance the following chemical equation

12. Why is respiration considered an exothermic process?

13. How does the flow of acid rain water into a river make the survival of aquatic life in the river difficult?

14. Draw the following diagram in your answer-book and show the formation of image of the object AB with the help of suitable rays.

15.Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?

16. Out of 60 W and 40 W lamps, which one has a higher electrical resistance when in use?

17. Write the chemical formula for washing soda. How many it be obtained from baking soda? Name an industrial use of washing soda other than washing clothes.

18. Give an example of a decomposition reaction. Describe an activity to illustrate such a reaction by heating.

19. Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed.

20. What is meant by the term, 'magnetic field'?  Why does a compass needle show deflection when brought near a bar magnet?

21.(a)Why are covalent compounds generally poor conductors of electricity?

(b)Name the following compound:

(c)Name the gas evolved when ethanoic acid is added to sodium carbonate. How would you prove the presence of this gas?

22. (a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides:

(b) Why is that non-metals do not displace hydrogen from dilute acids?

23. Two lamps, one rated 60W at 220 V and the other 40W at 220 V, are connected in parallel to the electric supply at 220V.

(a)  Draw a circuit diagram to show the connections.

(b)Calculate the current drawn from the electric supply.

(c)Calculate the total energy consumed by the two lamps together when they operate for one hour.