CBSE
Class 10
Class 12
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General Instructions:
1. | What is a reflex action? | [1] |
2. | Name the methods of asexual reproduction. | [1] |
3. | Write the group member with atomic number for each of the following elements: (i) F (at. no. 9) (ii) K (at. no. 19) | [2] |
4. | Which type of phenomenon (reflection or refraction) occurs when light falls on (i) a highly polished surface like a mirror and (ii) a transparent medium like glass or water? | [2] |
5. | Explain, why are fossil fuels classified a non-renewable sources of energy? | [2] |
6. | Balance the following chemical equations: | [3] |
7. | When hydrochloric acid is added to marble pieces, a gas (A) is evolved. On passing gas A through lime water, a white precipitate of (B) is formed. When excess of A is passed, B dissolves due to the formation of soluble C. Identify A, B and C. Explain the reactions. | [3] |
8. | How is the problem of dobling of the amount of DNA solved ? | [3] |
9. | What is the full form of ATP? How is it form? How much energy it releases when broken down? What are its uses? | [3] |
10. | The following table shows the position of six elements A, B, C, D, E and ![]() Using the above table answer the following questions: (a) Which element will form only covalent compounds? | [3] |
11. |
The sex of a newborn child is a matter of chance and none of the parents may be considered responsible for it. Justify this statement with the help of flow chart showing determination of sex of a newborn. | [3] |
12. | By drawing ray diagrams, explain the formation of image when an object is placed on the principal axis of a convex lens at the following positions: (i) At infinity (ii) Beyond 2F1 (iii) At 2F1 (iv) Between F1 and 2F1 (v) At focus F1 (vi) Between focus F1 and optical centre O. | [3] |
13. | An electric lamp, whose resistance is 20 Ω, and a conductor of 4 Ω resistance are connected to a 6 V battery. Calculate (a) the total resistance of the circuit, (b) the current through the circuit, and (c) the potential difference across the electric lamp and conductor.![]() Fig. An electric lamp connected in series with a resistor of 4 Ω to a 6 V battery | [3] |
14. | Define genetics. What is the contribution of Mendel in this branch of Biology? | [3] |
15. | The flow of current in a circular loop of wire creates a magnetic field at the centre. How may the existence of this field may be detected? State the rule which helps to predict the direction of the magnet field? ![]() | [3] |
16. | What happens when: (i) Lead is heated to 400–500°C in air. | [5] |
17. |
(a) In a tabular form, differentiate between ethanol and ethanoic acid under the following heads: (i) Physical state (ii) Taste (iii) NaHCO3 test (iv) Ester test (b) Write a chemical reaction to show the dehydration of ethanol. | [5] |
Classify the following compounds as alkane, alkene or alkyne.
C3H4, C2,H6 C2H4, C6H14, C2H2, C4H8, C5H12’ C5H8, C3H8
Explain, how did you arrive at your conclusion in each case.
18. | List the major endocrine glands found in human body. Write their functions. | [5] |
19. | Discuss the refraction of light through a prism. What are angle of deviation and angle of emergence? How are these angles related to the angle of incidence and the angle of prism? | [5] |
20. | Draw a schematic diagram of household/domestic wiring. Give its essential features. | [5] |
What was Chipko Andolan? How did the Andolan ultimately benefit the local people and the environment?
22. |
When you add about 2 ml of acetic acid to a test tube containing an equal amount of distilled water and leave the test tube to settle after shaking its contents, what will you observe in the test tube after about 5 minutes? | [2] |
A white precipitate settling at its bottom
A clear colorless solution
A layer of water over the layer of acetic acid.
A layer of water over the layer of acetic acid.
23. |
A student takes 2 mL acetic acid in a dry test tube and adds a pinch of sodium hydrogen carbonate to it. He makes the following observations: I. A colorless and odorless gas evolves with a brisk effervescence. II. The gas turns lime water milky when passed through it. III. The gas burns with an explosion when a burning splinter is brought near it. IV. The gas extinguishes the burning splinter that is brought near it. The correct observations are: | [2] |
I, II, and III
II, III and IV
III, IV and I
III, IV and I
24. |
During the course of an experiment, 'to determine the percentage of water absorbed by raisins', raisins are weighed | [2] |
every half an hour.
every hour.
once - only after completing the experiment.
once - only after completing the experiment.
25. |
Study the following diagrams showing various stages of binary fission in Amoeba: The correct sequence of these diagrams should be: | [2] |
I, IV, III,II, V
I, III, IV, II, V
I, II, IV, III, V
I, II, IV, III, V
26. |
Four students A, B, C and D traced the paths of incident ray and the emergent ray by fixing pins P and Q for incident ray and pins R and S for emergent ray for a ray of light passing through a glass slab. The correct emergent ray was traced by the student: | [2] |
27. | Of the following groups which one contains good conductors of electricity | [2] |