Monday, February 11, 2013

CBSE SCIENCE SAMPLE PAPER


Q.1. A Person is advised to wear spectacles with concave lens. What  type of defect of vision is he suffering from?

Q.2.What is the structural formula for ethanol?

Q.3.If all the waste we generate is biodegradable; will this have no impact on the environment?




Q.4. Rearrange the following according to their ascending trophic levels in a food chain: Eagle, Plants, insects, Frog

Q.5.Is the position of a star as seen by us is true position. Justify your answer.

Q.6.A mirror form 2 times real & inverted image when object is placed at a distance of 10cm. At what distance should an object be placed so that image is 3 times virtual & erect?

Q.7.Give reason:

(i)Danger signals are made of red colour.

(ii)The sky appears to be blue during day time to a person on earth.


Q.8.An element X is in second period & group 16 of the periodic table:

(i)Is it metal or non-metal?

(ii)What is its valency?

(iii)What will be the formula of compound of X with Na?


Q.9.How does electronegativity of an element vary on moving from:

(i) Left to right in a period.

(ii)Bottom to top in a group.


Q.10.(a)What is isomerism?

           (b)Draw the electron dot structure of CO2.


Q.11.What is meant by management & conservation of natural resources? Why must we conserve our forests?


Q.12.(a)What is the signification of sexual mode of reproduction?

           (b)What is the site of fertilization in human beings?


Q.13.(a)Why is cross-pollination considered to be superior than self-pollination?

           (b)State the method used for growing rose plants.


Q.14.(a)Convex mirror & a plane mirror forms virtual image. How will you distinguish between the two by looking at the images of an object?

          (b)When we focus sunlight using a convex lens at the tip of a matchstick, what will happen? Why?

Q.15.(a)State the reason for the following observation recorded from the surface of the moon:

            (i)Sky appears dark.

            (ii)Rainbow is never formed.

            (iii)Why does a diamond sparkle?


Q.16.(a)when white light hits a prism surface, why does it split into constituent colour?

           (b)The sun appears oval during evening hours. Why?


Q.17.(a)What is hydrogenation? Write one of its industrial application.

           (b)Why acetic acid is known as glacial acetic acid?


Q.18.(a)Write the names and structure of the compounds  HCOOH and  HCHO.

              (b)A mixture of oxygen &  ethyne is burnt for welding. Why do you think a mixture of ethyne & air is not used?


Q.19.Define variation in relation to a species. Why is variation beneficial to the species?


Q.20. Explain the importance of fossils in deciding evolutionary relationships.


Q.21. Distinguish between acquired & inherited traits by giving one example of each. Why are traits acquired during the lifetime of an individual not herited?


Q.22. Reproduction is essentially a phenomenon that is not for survival of an individual but for the stability of a species. Justify.


Q.23.(a)Is it possible to form a real image using a real object with a concave lens?

            (b)What is the emergent angle of light after refraction in a glass slab?

            (c)Define angle of prism.

OR

     (a)A person wants to see the full length image of tall building in a small mirror. what type of mirror is used by him?

    (b)Name a mirror that can give an erect & enlarged image of an object.

    (c)Magnification produced by a concave mirror of a body 4cm in size is 0.16. what is the size of the image?


Q.24. (a)Draw a labeled diagram to show the refraction through a triangular glass prism.

            (b) Define the angle of deviation

            (c) Write the factors on which angle of deviation depends

Or

(a) What is a homologous series of substances?

(b) In an organic compound, which parts largely determine its physical and chemical properties?

(c) Write a chemical equation to represent the reaction of ethanol with acidified solution of potassium dichromate.


Q.25.(a)How does the embryo get nourishment inside the  mother’s  body?

           (b)What are the functions of testes in human males?

           (c)Why does menstruation occur?

OR

(a)What are the different methods of contraception?

(b)Where are the vegetative buds present in Bryophyllum?

(c)Where does the formation of DNA copy occurs?

Q.26. The angle of incidence  i and reflection  r are equal during the refraction through a transparent slab ,the value of  i  is,

(a)0 °                    (b)45°                    ( c)90 °                     (d)depend on the material of the slab


Q.27. The self linkage property is maximum in.

(a) carbon         (b) silicon               (c) sulphur                (d) phosphorus


Q.28. As incident angle is decreased for the given pare of medium, the angle of refraction will ,

(a) increase      (b) decrease        (c) may increase or decrease     (d) always remains same


Q.29.The magnification of plane mirror is

(a) -1                 (b) +1                         (c) 0                                                    (d) Infinitive


Q.30. Which part of the bryophyllum plant help in vegetative propagation

(a) roots           (b) stem                    (c) leaves                                          (d) flowers  


Q.31. For a given medium the R.I is maximum for the color

(a) Red             (b)Blue                     (c)Violet                                        (d)Green.


Q.3. The boiling temperature of ethenoic acid is .

(a) 285 K          (b) 391K                    (c) 373K                                         (d) 413K

Q.33. The colour of copper sulphate solution is,

(a) colourless                          (b) yellow                    (c) orange                      (d) blue


Q.34. To prevent the misuse of alcohol which poisonous substance is added in it?

(a. Methanol                            (b.) Ethanol                (c.) Butanol                   (d.) Ether


Q.35. Which Substance is used as pickles preservative?

(a) Ether                                 (b) Acetic acid            (c) Vinegar                    (d) Ethanoic acid


Q.36. In modern periodic table how many columns are vertically arranged?

(a) 16                                      (b) 18                            (c) 14                               (d) 20


 Q.37. In an experiment to determine the focal length of a convex lens, a student obtained a sharp inverted image of distant tree on the screen behind the lens. He / She then removed the screen and looked through the lens in the direction of object. She / He will see. -

(a.) An inverted image of tree at focus of lens.     

(b.) No Image as the screen has been removed

(c.) A blurred image on the wall of laboratory

(d.) An erect image of the tree on the tree on the lens


Q.38. For doing experiment on verifying the Causes of reflection of light. A student sets up his apparatus as shown. The experiment is more likely is get preformed successfully if the screen shown is a.

(a) Well polished plane mirror

(b) Wooden board with many holes in it

(c) A foam padded board

(d) A sheet of pure white cloth


Q.39. The focal length of a concave mirror depends on it.

(a) Size                     (b) Radius of curvature           (c) Pole                  (d) Center of curvature


Q.40. The diameter of the reflecting surface of spherical mirror is called.

(a) Focal length     (b) Radius of curvature           (c) Aperture         (d) Principal focus

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