Guess Paper – 2011
Class – X
Subject - Science

SET-A

1. WHY IS HYDROGEN PEROXIDE KEPT IN COLOURLESS BOTTLES?

2. NAME THE CATALYST USED IN PREPARATION OF METHANOL BY USING WATER AND CARBON MONO-OXIDE?

3. WHAT IS GREEN VITROL?

4. GIVE EXAMPLE OF A COMPOUND WHICH SPLITS INTO ITS ELEMENTS BY PASSINGULTRA-VIOLET RAYS?

5. WHAT IS THERMO-CHEMICAL REACTION?

6. WHAT IS ALUMINOTHERMY?

7. GIVE AN EXAMPLE OF CHEMICAL REACTION IN WHICH BLUISH WHITE PRECIPITATE IS FORMED?
(HINT - COPPER HYDROXIDE IS A BLUISH WHITE PRECIPITATE )

8. NAME A SUBSTANCE FORMED WHEN SILVER IS EXPOSED TO AIR ?

9. WHAT IS CHEMICAL VOLCANO?

SET-B

1. Why is hydrogen collected over water?

2. Why is lime water slightly milky?

3. What is rust?

4. Name a metal which does not get rusted.

5. What is the role of oxidizing agent in a reaction?

6. Give two ways to check the rancidity of food articles?

7. What are neutralization reactions? Why are they so named? Give one example.?

8. Aluminium is a reactive metal but is still used for packing food articles. Why?

9. Identify the type of reaction in the follow
(a) P + Q ---> R
(b) P + QR ---->PR + Q
(c) P ---->Q + R
(d) PQ + RS----> PS + QR

10. Under what conditions can chemical decomposition be carried out? Give an example in each case.
11. What information is given by the chemical equation, given atomic mass of
Zn = 65 and Cl = 35.5
Zn(s)+ 2HCl_(aq)ZnCl_2aq)+ H_2(g)

SET-C

1) Name the screen on which eye forms the image.

2) Which color suffers least deviation on passing through a prism?

3) Which phenomenon is responsible for increasing the apparent length of the day by 4 minutes?

4) What is the basic cause of atmospheric reftraction?

5) What is the angle of deviation?

6) What is meant by power of accomodation?

7) Which lens is used to rectify myopia?

8) What is meant by refraction of light?

9) What makes the dust particles visible in atmosphere?

10) Why are the danger signals red in colour?

11) Name the two phenomenon associated with scattering of light.

12) If the size of the particles is very large, then which colour of light will be visible?

13) What is the colour of the space?

14) Why are we not able to see objects clearly for sometime when we enter from bright light to a dark room with dim light?

15) What is the function of iris, pupil and cilliary muscles?

16) What are bifocal lenses? Why are they used?

17) A person has normal vision , but he cannot distinguish between red – green colours , why?

18) Why we cannot read a printed page by holding it very close to our eyes?

19) What is meant by persistence of vision?

20) What name is given to front transparent part of human eye?

21) A student sitting at the back bench has difficulty in reading from the black board. Name the defect of his vision. How is the defect removed?

22) What is the cause of dispersion of light?

23) Draw labeled diagram to show the dispersion of light.

24) How does the rainbow formation take place?

25) By drawing the labeled diagram of human eye, explain its structure.

26) The far point of a myopic eye is 80 cm in front of the eye. What is the power of the lens required to enable him to see far off objects?

27) Why do stars twinkle whereas planets dont?

28) What is meant by scattering of light?

29) Why do different colours deviate at different angles on passing through prism?

30) Why does sky appears blue?

31) What is myopia and hypermetropia? How can the two corrected? Explain with the help of diagrams.

32) Why does sun appears reddish in the morning?

33) The near point of hypermetropic eye is at 75 cm from the eye. What is the power of the lens required to enable him to read clearly a book held at 25 cm from the eye?

34) In which direction the rainbow appears?

35) What is the least distance of distict vision?

36) Which phenomenon of vision is used in photography?

37) What enables the eye to focus objects at different distances?

38) Why stars appear higher than they actually are?

39) Calculate maximum power of accommodation of person having normal vision.?

40) Expand VIBGYOR.?