Question 1

1. On what basis is a chemical equation balanced?

Question 2

2. How is the pH of a solution of an acid influenced when it is diluted?

Question 3

3. Show the electronic transfers in the formation of from its elements.

Question 4

4. Which kind of mirrors are used in the headlights of a motor-car and why?

Question 5

5. How is an electromagnet different from a permanent magnet?

Question 6

6. In the circuit diagram shown, the two wires X and Y are of the same length and same metal, but X is thicker than Y. Which ammeter will indicate a higher current strength?

Question 7

7. State any two observations in an activity which may suggest that a chemical reaction has taken place. Give examples to support your answer.

Question 8

8. How is Plaster of Paris prepared? Why is Plaster of Paris stored in an air-tight container?

Question 9

9. A ray of light, incident obliquely on a face of a rectangular glass slab placed in air, emerges from the opposite face parallel to the incident ray. State two factors on which the lateral displacement of the emergent ray depends.

Question 10

10. How can it be shown with the help of an activity that a magnetic field is produced round a current carrying wire?

Question 11

11.Table given below shows a part of the Periodic Table.

Question 12

12. (a)What is a functional group in a carbon compound? Identify the functional group present in



(b)State the principle on which the cleansing action of a soap is based.

Question 13

13. An electric lamp of 200Ω and a toaster of 100Ω are connected in parallel to a 220 V electricity source.


(a)What will be the resistance of an electric iron which when connected to the same electric source permits the same current as the total current flowing through both the appliances described above?

(b)What is the current passing through the electric iron?

(c)Calculate the power of the electric iron.

Question 14

14.Describe an activity to find the relationship between the potential difference across the two ends of a conductor and the current flowing through it by including in your answer the following:

(i)Diagram of the electric circuit.

(ii) an observation table.

(iii) a V-I graph.

Question 15

15.Sample pieces of 5 metals A, B,C, D and E were added to the tabulated solutions separately.

Question 16

16.(a)It is desired to obtain an erect image of an object, using a concave mirror of focal length 20cm.

(i)What should be the range of distance of the object from the mirror?

(ii)Will the image be bigger or smaller than the object?

(iii)Draw a ray diagram to show the image formation in this case.

(b)One half a convex lens of focal length 20cm is covered with a black paper.

(i)Will the lens produce a complete image of the object?

(ii)Show the formation of image of an object placed at 2F₁ of such covered lens with the help of a ray diagram.

(iii)How will the intensity of the image formed by half-covered lens compare with non-covered lens?

(a)What is hypermetropia?

(b)What are the two causes of this defect of vision?
(c)How can this defect of the eye be corrected? Illustrate your answer by drawing ray diagram to show the formation of image by (i)a hypermetropic eye,(ii)a hypermetropic eye corrected with a suitable lens.

Question 17

17.List any two traditional systems of water harvesting.

Question 18

18.Which pancreatic enzyme is effective in digesting proteins?

Question 19

19.What is the function of the hormone secreted by the endocrine gland, pituitary?

Question 20

20.What are fossil fuels?Give two examples of fossil fuels.

Question 22

22.What is reflex action?Explain the mechanism of reflex action with a suitable example.

Question 23

23.Describe briefly four ways in which individuals with a particular trait may increase in a population.

Question 24

24.How are fats digested in out body?Where does this process take place?

Question 25

25. What are stomata? Draw a labeled diagram of stomata. Write two functions of stomata.

Question 26

26.(a)Distinguish between producers and decomposers.

(b)Classify the following as producers and decomposers

Green plants, Bacteria, Fungi, Blue-green algae.

Question 27

27.(a)Draw a diagram illustrating fertilization in a flowering plant and label on it.

Pollen grain, Male germ cell, Female germ cell, Stigma.

(b)Describe the process of fertilization in plants.

(a)Draw a diagram showing longitudinal section of a flower and label on it: Stigma, Ovary, Anther, Filament.

(b)How is the process of pollination different from fertilization?