SCIENCE - Guess Paper - 2
Time Allowed: 3 hours Maximum Marks: 80
General Instructions:
- This question paper consists of 39 questions in 5 sections.
- All questions are compulsory. However, an internal choice is provided in some questions. A student is expected to attempt only one of these questions.
- Section A consists of 20 objective-type questions carrying 1 mark each.
- Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions should be in the range of 30 to 50 words.
- Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these questions should be in the range of 50 to 80 words.
- Section D consists of 3 Long Answer type questions carrying 05 marks each. Answers to these questions should be in the range of 80 to 120 words.
- Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts.
SECTION - A
1. A student added dilute HCl to a test tube containing zinc granules and made following observation:
(i)Zinc surface become dull and black
(ii) A gas evolved which burnt with a
pop sound
(iii)The solution remained colourless
(a) i and ii (b) i and iii
(b) (c) ii and iii (d) i, ii and iii
2. A metal gives lilac colour in bunsen flame and the solution of its oxide turns red litmus
paper blue. The metal is?
(a) Νa (b) K (c)Ca (d) Li
3. KMnO4 + H2SO4 + FeSO4 → K2SO4 + MnSO4 + Fe2(SO4)3 + H2O
Coefficients of sulphuric acid and ferric sulphate in the balanced equation of above
reaction are _______ and _________ respectively.
(a) 8,4 (b) 5,8 (c)4,3 (d) 8,5
4. Anhydrous iron (III) chloride is prepared by:
(a) Combination (b)displacement
(c)decomposition (d)neutralization
5. Equal volumes of solutions containing 1 mole of an acid and 1 mole of a base
respectively are mixed. Which of these mixture will give pH more than 7?
( a) Sodium hydroxide + Acetic acid (b)Potassium hydroxide + Sulphuric acid
(c) Ammonium hydroxide + Sulphuric acid (d) Sodium hydroxide + Hydrochloric acid
6. Which of the following statements is not correct?
(a)All metal carbonates react with acid to give a salt, water and carbon dioxide
(b)All metal oxides react with water to give salt and acid
(c)Some metals react with acids to give salt and hydrogen
(d)Some non-metal oxides react with water to form an acid
7. Rectified spirit is a mixture of:
(a)95% ethyl alcohol + 5% water (b) 94% ethyl alcohol + 4.53% water
(c)94.4% ethyl alcohol + 5.43% water (d)95.57% ethyl alcohol + 4.43% water
8. Soft soap are
(a)Sodium salt (b)Calcium salt
(c)magnesium salt (d)potassium salt
9. The time required to pass the light through a glass slab of 2 mm thick is (μglass = 1.5)
(a) 10-5s (b) 10-11s (c)10-9 s (d) 10-13 s
10. A medium shows the relation between the angle of incidence i and the angle of refraction r. If speed of light in the medium is nc then value of n is
(a) 2-1 (b) 2 (c)1.5 (d) 3-1/2
11. A large-angle prism deviates a light ray
(a)more (b)less (c)equal to a small-angle prism (d) does not deviate at all
12. Anil, an 8th grade student, was asked to draw a figure explaining how the mammalian eye collects and focuses light, converting it into electrical signals.
Which of the following flow charts correctly represents the process?
(a)Light → Cornea → Aqueous humor → Pupil→ Lens →Vitreous humor → Retina
→Action potentials in neurons→ Optic nerve → Brain.
(b)Light → Sclera → Vitreous humor → Pupil → Lens → Aqueous humor → Retina
→Action potentials in neurons→ Optic nerve Brain.
(c)Light → Sclera → Cornea Aqueous humor → Pupil → Lens → Vitreous humor →
Retina → Action potentials in neurons → Optic nerve → Brain.
(d)Light → Cornea → Aqueous humor→ Iris → Lens →Vitreous humor → Retina →
Action potentials in neurons → Optic nerve → Brain.
13. A bulb rated at (100W-200V) is used on a 100 V line. The current in the bulb is
(a)1/4 amp (b) 4 amp (c) 1/2 amp (d)2 amp
14. The reading of the ammeter is:
(a)1/8A (b)2 A (c) 3/4 A (d) 1/2 A
15. A boy was making a model of an electric bell. He connected the coil in the circuit and switched it on. However, the magnetism produced in the coil was not strong enough. He made some changes in the coil and the circuit was now working.
What changes did the boy make in the coil?
(a)Decrease in the number of turns in the coil (b) Replaced the coil
(c)Increase in the number of turns in the coil (d) All of the above
16. If a bar magnet is cut into 'n' pieces, how many poles will each magnet have?
(a)1 (b)2 (c) 0 (d) n
17. Assertion (A): HCl is a stronger acid than acetic acid.
Reason (R): On dissociation, HCl yields lesser hydrogen ions for the same concentration as compared to acetic acid.
(a) Both A and R are true and R is the correct (b) Both A and R are true but R is not the explanation of A. correct explanation of A.
(c) A is true but R is false. (d) A is false but R is true
18. Assertion(A): Olefins have the general formula CnH2n+1
Reason (R): There is at least one double bond between two carbon atoms in their
molecules.
(a) Both A and R are true and R is the correct (b) Both A and R are true but R is not the explanation of A. correct explanation of A.
(c) A is true but R is false. (d) A is false but R is true
19. Assertion (A): The coil of a heater is cut into two equal halves and only one of them is used into heater. The heater will now require half the time to produce the same amount of heat.
Reason (R): The heat produced is directly proportional to square of current.
(a) Both A and R are true and R is the correct (b) Both A and R are true but R is not the explanation of A. correct explanation of A.
(c) A is true but R is false. (d) A is false but R is true
20. Assertion (A): A rainbow is sometimes seen in the sky in rainy season only when observer's back is towards the Sun.
Reason (R): Internal reflection in the water droplets cause dispersion and the final rays are in backward direction.
(a) Both A and R are true and R is the correct (b) Both A and R are true but R is not the explanation of A. correct explanation of A.
(c) A is true but R is false. (d) A is false but R is true
SECTION - B
21. A metal wire of resistance 3Ω is elongated to make a uniform wire of double its previous length. This new wire is now bent and the ends joined to make a circle. If two points on this circle make an angle 60º at the centre, the equivalent resistance between these two points will be?
22. What happens when a second identical prism is placed in an inverted position with respect to the first prism? Draw a labeled ray diagram to illustrate it.
23. Distinguish between Overloading and Short circuiting in Domestic circuit.
24. What is the nature of reaction involved in the dilution of acid?
25. Why are organic compounds present in such a large number?
26. Which property of solder alloy makes it suitable for welding electrical wires?
SECTION - C
27. When hydrogen sulphide gas is passed through a blue solution of copper sulphate, the colour of the solution fades and a black precipitin is obtained.
(a) Name the type of reaction mentioned above.
(b) Why does the colour of the solution fades away?
(c) Write the chemical name of the black precipitate formed.
(d) Give the balanced chemical equation for the reaction involved.
28. (a) For the same angle of incidence of 45°, the refraction angle in two transparent media P and Q is 20° and 30° respectively. Which of the two is optically denser and why?
(b) Define 1 dioptre power of a lens
(c) Find the focal length denser and why?
29. (a) Explain with the help of the pattern of magnetic field lines the distribution of magnetic field due to a current carrying a circular loop.
(b) Why is it that the magnetic field of a current carrying coil having n turns, is 'n' times as large as that produced by a single turn (loop)?
30. (a) Draw the structures for (i) ethanol, (ii) ethanoic acid.
(b) Why is the conversion of ethanol to ethanoic acid considered an oxidation reaction? Write the oxidising agent used in the reaction involved.
31. (iv) Complete and balance the following chemical equations:
(a) C2H6 + O2 →
(b) C2H2 + I2 →
(c) NH3 + HCl →
32. (i) Name the metal which does not stick to glass?
(ii) Name the non-metal which is a good conductor of electricity?
(iii) Name the metal which is commonly used in thermit welding?
(iv) What gets deposited at the cathode, a pure or impure metal?
(v) What is the nature of Zinc oxide?
33. (a) Write the mathematical expression for Joule's law of heating,
(b) Compute the heat generated while transferring 96000 coulomb of charge in two hours through a potential difference of 40 V.
SECTION - D
34. List four characteristics of the image formed by a concave lens of focal length 20 cm when the object is placed at a distance of 40 cm from its optical centre.
The size of image of an object by a convex lens of focal length 20 cm is observed to be reduced to 1/3rd of its size. Find the distance of the object from the optical centre of the lens.
35. (a) The blue color of crystals of a substance on heating in a closed test tube gets changed but the color was regained after sometime on cooling. Name that substance and write its chemical formula. Explain the phenomenon involved.
(b) Write name and chemical formulae of two such compounds whose one unit is
associated with 10 and 2 water molecules respectively
36. Figure shows a 240 V A.C mains circuit to which a number of appliances are connected and switched on.
(i) Calculate the power supplied to the circuit.
(ii) Calculate:
a. the current through the refrigerator,
b. the energy used by the fan in 3 hours,
c. the resistance of the filament of one lamp.
SECTION - E
37. Read the text carefully and answer the questions:
Salt of a strong acid and strong base is neutral with a pH value of 7. NaCl common salt is formed by a combination of hydrochloride and sodium hydroxide solution. This is the salt that is used in food. Some salt is called rock salt, bed of rock salt was formed when seas of bygone ages dried up. The common salt thus obtained is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, and bleaching powder.
(i) If given acids are phosphoric acid, carbonic acid, hydrochloric acid and sulphuric acid, then which acid does not form an acidic salt?
(ii) What is the formula of baking soda?
(iii) Name the substance which on treatment with chlorine to obtain bleaching powder.
(OR)
Which salt is used for removing the permanent hardness of water?
38. Read the text carefully and answer the questions:
Two or more resistances are connected in series or in parallel or both, depending upon whether we want to increase or decrease the circuit resistance.
The two or more resistances are said to be connected in series if the current flowing
through each resistor is the same.
(i) When the three resistors each of resistance R ohm are connected in series then what will be the equivalent resistance?
(ii) There is a wire of length 20 cm and having resistance 20 Ω cut into 4 equal pieces and then joined in series. What is equivalent resistance?
(OR)
In the following circuit, find the equivalent resistance between A and B (R = 2Ω)
39. Read the text carefully and answer the questions:
When oxygen combines with other elements or compounds, the process is called
oxidation the substances that combine with oxygen are said to have been oxidized.
The reduction is exactly the opposite of oxidation. If a substance loses oxygen during a reaction, it is said to be reduced. When hydrogen burns the hydrogen combines with oxygen to form water 2H2 + O2 = H2O
The hydrogen is oxidized in this reaction, but at the same time, the oxygen is reduced.
Whatever oxidation occurs reduction must also occur.
(i) Which chemical process is used for obtaining a metal from its oxide?
(ii) In the given reaction, which reactant species is oxidized?
(iii) In the given reaction, which reactant species is reduced?
(OR)
If four molecules of Hydrogen are combined with oxygen then how many molecules of water are formed?
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