X SCIENCE SA-I M.M:80
SECTION A
1. Name the acid present in ant sting.
2. What does the direction of thumb indicate in the right-hand thumb rule.
3. Name the plant hormones responsible for elongation of cells.
4. What steps would you suggest to minimise environmental pollution caused by burning of fossil fuels?
5. For making cake, baking powder is taken. If at home your mother uses baking soda instead of baking powder in cake,
(a) how will it affect the taste of the cake and why?
(b) how can baking soda be converted into baking powder?
6. In one of the industrial processes used for manufacture of sodium hydroxide, a gas X is formed as by product. The gas X reacts with dry slaked lime to give a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y
7. What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?
8. A battery of 9 V is connected in series with resistors of 0.2Ω, 0.3 Ω, 0.4 Ω , 0.5 Ω ,and 12 Ω resistors. How much current would flow through the 2f resistor?
9. A child has drawn the electric circuit to study Ohm’s law as shown in Figure. His teacher told that the circuit diagram needs correction. Study the circuit diagram and redraw it after making all corrections.
10. AB is a current carrying conductor in the plane of the paper as shown in Figure. What are the directions of magnetic fields produced by it at points P and Q? Given r1 > r2, where will the strength of the magnetic field be larger?
11. How do the guard cells regulate opening and closing of stomatal pores?
12. “All plants give out oxygen during day and carbon dioxide during night”. Do you agree with this statement? Give reason.
13. What happens at the synapse between two neurons?
14. Differentiate mineral, ore and gangue.
15. In the following schematic diagram for the preparation of hydrogen gas as shown in Figure, what would happen if following changes are made?
(a) In place of zinc granules, same amount of zinc dust is taken in the test tube.
(b) Instead of dilute sulphuric acid, dilute hydrochloric acid is taken.
(b) Sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated.
16. When a metal X is treated with cold water, it gives a base Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.
17. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
18. What is meant by the ‘magnetic field lines’? List any two properties of magnetic field lines?
19. What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads 5 A. The reading of the ammeter decreases to half when the length of the wire is doubled. Why?
20. What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?
21. Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reasons for your answer.
22. What are reflex actions? Give two examples. Explain a reflex arc.
23. Observe the given figure and answer the following questions.
(1) Write the complete balanced reaction for the above.
(2) Type of reaction involved.
(3) Is there any precipitate formed.
(4) If any precipitate formed, write the colour of the precipitate.
OR
A student dropped few pieces of marble in dilute hydrochloric acid, contained in a test tube. The evolved gas was then passed through lime water. What change would be observed in lime water. What will happen if excess of gas is passed through lime water. Write balanced chemical equations for all the changes observed.
24. Shown in the diagrams (a), (b), (c) and (d) are the magnetic fields around different systems. Identify them. Compare the pattern of the fields in all the four examples. Are they similar? Why?
OR
Describe the activity that shows that a current-carrying conductor experiences a force perpendicular to its length and the external magnetic field. How does Fleming’s left-hand rule help us to find the direction of the force acting on the current carrying conductor?
25. Draw a neat diagram of internal structure of human heart and label the parts which do the following functions.
(a) chamber where oxygenated blood from lungs is collected
(b) largest blood vessel in our body
(c) muscular wall separating right and left chambers
(d) blood vessel that carry blood from heart to the lungs.
OR
State three main events occuring during photosynthesis. Write the over all equation for photosynthesis and the site for photosynthesis.
SECTION B
26. A student took the following samples to find out their pH using pH paper. The teacher remarked that one of the samples taken was not proper. The teacher was referring to.
(a) Dilute hydrochloric acid (b) Lemon juice
(c) Washing soda (d) Soap solution
27. Four students a, b, c and d of class x measured the pH value of each one of the given samples of distilled water, acetic acid, dil hydrochloric acid and sodium hydroxide solution using pH papers. Which one of the following represents a correct measurement
Student (a) (b) (c) (d) | Water 7 8 7 7 | Acetic acid 1 3 1 3 | hydrochloric acid 3 1 3 1 | Sodium hydroxide 1 1 13 13 |
28. When zinc reacts with dilute hydrochloric acid.
(a) The surface of zinc becomes brighter
(b) The surface of zinc becomes black and dull
(c) The metal turns into powder
(d) The reaction mixture turns green
29. A drop of colourless liquid was placed on blue litmus paper. The litmus paper turned red. The liquid could be
(a) Dilute hydrochloric acid (b) Dil. Sodium hydroxide solution
(c) Distilled water (d) Sodium bicarbonate solution
30. Aqueous solutions of zinc sulphate and iron sulphate were taken in test tubes I and II by four students A, B, C and D. Metal pieces of iron and zinc were dropped, in the two solution and observations made after several hours and recorded in the form of a table as given below.
Observation by A B C D | Metal Fe Zn Fe Zn Fe Zn Fe Zn | Solution ZnSO4 FeSO4 ZnSO4 FeSO4 ZnSO4 FeSO4 ZnSO4 FeSO4 | Colour change of solution turned green no change no change colour faded no change turned colourless no change no change | Deposit/residue obtained Silvery grey coating no change black residue grey coating no change black residue grey residue black residue |
The correct reporting has been made in observation reported by the student.
(a) A (b) B (c) C (d) D
31. Diagram showing a microscopic view of epidermal tissue
(a) is correct in all aspects
(b) is wrong because stoma is not shown
(c) is wrong because the guard cells are directed backwards
(d) is correct because two guard cells stomata are present
32. 10 ml of freshly prepared iron sulphate solution was taken in each of four test tubes. Strips of copper, iron, zinc and aluminium were introduced, each metal in a different test tube. A black residue was obtained in two of them. The right pair of metals forming the precipitate is
(a) copper and zinc (b) aluminium and copper
(c) iron and aluminium (d) zinc and aluminium
33. Which is the correct figure representing Ohm’s Law?
(a) (i) only (b) (i) and (ii) (c) (ii) only (d) (ii) and (iii)
34. In the experiment on finding the equivalent resistance of two resistors, connected in parallel, three students connected the voltmeter in their circuits, in three ways X, Y and Z shown here.
The voltmeter has been correctly connect in H
(a) cases X and Y only (b) cases Y and Z only
(c) cases Z and X only (d) all the three cases
35. A student has to connect 4 cells of 1.5V each to form a battery of 6V. Which arrangement is correct.
(a) A (b) B (c) C (d) D
36. Three students (A), (B) and (C). Connect their two given resistors R1 and R2 in the manners shown
They record the ammeter readings (I) for different positions of the rheostat and the corresponding voltmeter reading (V). The average value of the ratio (V/I) in their observations would be minimum for
(a) student A and B only (b) student B and C only
(c) student C and A only (d) student A only
37. Which of the circuit components in the adjoining circuit diagram are connected in parallel?
(a) R1 and R2 only (b) R2 and V only
(c) R1 and V only (d) R1, R2 and V
38. In an experiment to show that sunlight is necessary for photosynthesis, the leaf is boiled in alcohol for a few minutes using a water bath. Water bath is essential because H
(a) alcohol is highly volatile
(b) steam from the water bath heats the leaf rapidly
(c) steam from the water bath dissolves the chlorophyll
(d) alcohol is inflammable
39. Given here is a sketch of a leaf partially covered with black paper and which is to be used in the experiment to show that light is compulsory for the process of photosynthesis. At the end of the experiment, which one of the leaf parts labelled. I, II and III will become blue black when dipped in iodine solution.
(a) I only (b) II only
(c) I and III (d) II and III
40. After performing the experiment to show that germinating seeds give out carbon dioxide during respiration student drew the following diagrams.
The correct labelled diagram is
(a) A (b) B (c) C (d) D
41. The teacher instructed a student to place a healthy potted shoe flower plant in a dark room for 24 hours prior to an experiment on photosynthesis. The purpose of placing it in a dark room is.
(a) to increase the intake of CO2
(b) to activate the chloroplasts in the leaves
(c) to destarch the leaves
(d) to denature the enzymes in the leaves
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