| Write chemical equation of the reaction of ethanoic acid with the following: |
| (a) Sodium; |
| (b) Sodium hydroxide; |
| (c) Ethanol. |
| Write the name of one main product of each reaction. |
| An element 'X' belongs to 3rd period and group 16 of the Modern Periodic Table. |
| (a) Determine the number of valence electrons and the valency of 'X'. |
| (b) Molecular formula of the compound when 'X' reacts with hydrogen and write its electron dot structure. |
| (c) Name the element X' and state whether it is metallic or non-metallic. |
| (a) List two reasons for the appearance of variations among the progeny formed by sexual reproduction. |
| (b) |
 |
| (i) Name the part marked 'A' in the diagram. |
| (ii) How does 'A' reaches part 'B'? |
| (iii) State the importance of the part 'C'. |
| (iv) What happens to the part marked 'D' after fertilisation is over? |
| The activities of man had adverse effects on all forms of living organisms in the biosphere. Unlimited exploitation of nature by man disturbed the delicate ecological balance between the living and non-living components of the biosphere. The unfavourable conditions created by man himself threatened the survival not only of himself but also of the entire living organisms on the mother earth. One of your classmates is an active member of ?Eco club? of your school which is creating environmental awareness amongst the school students, spreading the same in the society and also working hard for preventing environmental degradation of the surroundings. |
| (a) Why is it necessary to conserve our environment? |
| (b) State the importance of green and blue dust-bins in the safe disposal of the household waste. |
| (c) List two values exhibited by your classmate who is an active member of Eco-club of your school. |
| It is desired to obtain an erect image of an object, using concave mirror of focal length of 12 cm. |
| (i) What should be the range of distance of an object placed in front of the mirror? |
| (ii) Will the image be smaller or larger than the object. Draw ray diagram to show the formation of image in this case. |
| (iii) Where will the image of this object be, if it is placed 24 cm in front of the mirror? Draw ray diagram for this situation also to justify your answer. |
| Show the positions of pole, principal focus and the centre of curvature in the above ray diagrams. |
| (a) Define optical centre of a spherical lens. |
| (b) A divergent lens has a focal length of 20 cm. At what distance should an object of height 4 cm from the optical centre of the lens be placed so that its image is formed 10 cm away from the lens. Find the size of the image also. |
| (c) Draw a ray diagram to show the formation of image in above situation. |
| What is atmospheric refraction? Use this phenomenon to explain the following natural events. |
| (a) Twinkling of stars |
| (b) Advanced sun-rise and delayed sun-set. |
| Draw diagrams to illustrate your answers. |
| A student puts a drop of reaction mixture of a saponification reaction first on a blue litmus paper and then on a red litmus paper. He may observe that: |
| (a) There is no change in the blue litmus paper and the red litmus paper turns white. |
| (b) There is no change in the red litmus paper and the blue litmus paper turns red. |
| (c) There is no change in the blue litmus paper and the red litmus paper turns blue. |
| (d) No change in colour is observed in both the litmus papers. |
| For preparing soap in the laboratory we require an oil and a base. Which of the following combinations of an oil and a base would be best suited for the preparation of soap? |
| (a) Castor oil and calcium hydroxide |
| (b) Turpentine oil and sodium hydroxide |
| (c) Castor oil and sodium hydroxide |
| (d) Mustard oil and calcium hydroxide |
| In the neighbourhood of your school, hard water required for an experiment is not available. Select from the following groups of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard: |
| (a) Sodium chloride, calcium chloride |
| (b) Potassium chloride, sodium chloride |
| (c) Sodium chloride, magnesium chloride |
| (d) Calcium chloride, magnesium chloride |
| A student while observing an embryo of a pea seed in the laboratory listed various parts of the embryo as given below: |
| Testa, Tegmen, Radicle, Plumule, Micropyle, Cotyledon. |
| On examining the list the teacher remarked that only three parts are correct. |
| Select three correct parts from the above list: |
| (a) Testa, Radicle, Cotyledon |
| (b) Tegmen, Radicle, Micropyle |
| (c) Cotyledon, Plumule, Testa |
| (d) Radicle, Cotyledon, Plumule |
| If you are asked to select a group of two vegetables, out of the following, having homologous structures which one would you select? |
| (a) Carrot and radish |
| (b) Potato and sweet potato |
| (c) Potato and tomato |
| (d) Lady finger and potato |
| To determine the approximate value of the focal length of a given concave mirror, you focus the image of a distant object formed by the mirror on a screen. The image obtained on the screen, as compared to the object is always: |
| (a) Laterally inverted and diminished |
| (b) Inverted and diminished |
| (c) Erect and diminished |
| (d) Erect and highly diminished |
| Suppose you have focused on a screen the image of candle flame placed at the farthest end of the laboratory table using a convex lens. If your teacher suggests you to focus the parallel rays of the sun, reaching your laboratory table/ on the same screen, what you are expected to do is to move the: |
| (a) lens slightly towards the screen |
| (b) lens slightly away from the screen |
| (c) lens slightly towards the sun |
| (d) lens and screen both towards the sun |
| In your laboratory you trace the path of light rays through a glass slab for different values of angle of incidence \[\mathbf{(}\angle \mathbf{i)}\] and in each case measure the values of the corresponding angle of refraction \[\mathbf{(}\angle r\mathbf{)}\] and angle of emergence\[\mathbf{(}\angle e\mathbf{)}\]. |
| On the basis of your observations your correct conclusion is: |
| (a) \[\angle i\] is more than \[\angle r,\] but nearly equal to \[\angle e\] |
| (b) \[\angle i\] is less than \[\angle r,\] but nearly equal to \[\angle e\] |
| (c) \[\angle i\] is more than \[\angle e,\] but nearly equal to \[\angle r\] |
| (d) \[\angle i\] is less than \[\angle e,\] but nearly equal to \[\angle r\] |
| In the following ray diagram the correctly marked angle are: |
 |
| (a) \[\angle i\] and \[\angle e\] |
| (b) \[\angle A\] and \[\angle D\] |
| (c) \[\angle i,\,\angle e\] and \[\angle D\] |
| (d) \[\angle r,\,\angle A\] and \[\angle D\] |
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