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I, 2012

SUMMATIVE ASSESSMENT – I, 2012

/ SCIENCE

X / Class – X

3 90

Time allowed : 3 hours Maximum Marks : 90

(i)

(ii)

(iii)

(iv)

(v) 1 3

(vi) 4 7 30

(vii) 8 19 50

(viii) 20 24 70

(ix) 25 42

General Instructions :

(i) The question paper comprises of two Sections, A and B. You are to attempt both the

sections.

(ii) All questions are compulsory.

(iii) There is no overall choice. However, internal choice has been provided in all the five

questions of five marks category. Only one option in such questions is to be attempted.

(iv) All questions of Section-A and all questions of Section-B are to be attempted separately.

(v) Question numbers 1 to 3 in Section-A are one mark questions. These are to be answered in

one word or in one sentence.

(vi) Question numbers 4 to 7 in Sections-A are two marks questions. These are to be answered

in about 30 words each.

(vii) Question numbers 8 to 19 in Section-A are three marks questions. These are to be answered

in about 50 words each.

(viii) Question numbers 20 to 24 in Section-A are five marks questions. These are to be answered

in about 70 words each.

(ix) Question numbers 25 to 42 in Section-B are multiple choice questions based on practical

skills. Each question is a one mark question. You are to select one most appropriate

response out of the four provided to you.

SC2-015

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/ SECTION - A

1.

Mention the angle between a current carrying conductor and magnetic field for which the force experienced by this current carrying conductor placed in magnetic field is largest ?

1

2.

Name the sensory receptors found in the nose and on the tongue ?

1

3.

Define a solar panel.

1

4.

III

Write the balanced chemical equation for the following reaction and identify the type of reaction and define it. ‘Iron III oxide reacts with Aluminium and gives molten iron and aluminium oxide’.

2

5.

(a)

(b)

(c)

(d)

Name the following : (a) A metal which is preserved in kerosene (b) A lustrous coloured non metal (c) A metal which can melt while kept on palm. (d) A metal, which is a poor conductor of heat.

2

6. 800 W 6 30 ` 3.00

An electric heater rated 800 W operates 6 h/day. Find the cost of energy to operate it for 30 days at ` 3.00 per unit.

2

7.

Draw magnetic field lines produced around a current carrying straight conductor passing through cardboard. How will the strength of the magnetic field change, when the point where magnetic field is to be determined, is moved away from the straight wire carrying constant current ? Justify your answer.

2

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8.

(i)

(ii)

A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on the above information answer the following questions. (i) Name the metal and the black coloured substance formed. (ii) Write balanced chemical equations for both the reactions.

3

9. (a)

(b)

H2 SCl2 2 HClS

(c)

(a) Give an example for a combination reaction which is exothermic. (b) Identify the oxidising agent, reducing agent in the following reaction.

H2 SCl2 2 HClS

(c) Name the phenomenon due to which the taste and smell of oily food changes when kept for a long time in open. Suggest one method to prevent it.

3

10. (a)

(b) pH

(c)

(a) Write the name given to bases that are highly soluble in water ? Give an example. (b) How is tooth decay related to pH ? How can it be prevented ? (c) Why does bee sting cause pain and irritation ? Rubbing of baking soda on the sting area gives relief. How ?

3

11. (a)

(b)

(c)

(a) Why is calcium starts floating when added to water ? (b) Most of the metals do not give hydrogen while reacting with nitric acid. Why ? (c) Write equation for the reaction of iron with steam. Name the compound of iron obtained.

3

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12. (a) ‘l’ ‘r’ 10

(i)

(ii)

(b)

(a) Nichrome wire of length l and radius ‘r’ has resistance of 10 . How would the resistance of the wire change when : (i) Only length of the wire is doubled ? (ii) Only diameter of the wire is doubled ? Justify your answer. (b) Why element of electrical heating devices are made up of alloys ?

3

13. 5 , 10 15 30V

10

Three resistors of 5 , 10 and 15 are connected in series and the combination is connected to battery of 30V. Ammeter and voltmeter are connected in the circuit. Draw a circuit diagram to connect all the devices in proper correct order. What is the current flowing and potential difference across 10 resistance ?

3

14.

What is meant by overloading of an electrical circuit ? Explain two possible causes due to which overloading may occur in household circuit ? Explain one precaution that should be taken to avoid the overloading of domestic electric circuit.

3

15. (a)

(b)

(a) Explain with the help of diagram, how amoeba takes its nutrition. (b) Assume that you are a veterinary surgeon and you had removed a good length of the small intestine of a bear that was suffering from a intestinal tumor. Now, would you suggest a plant based or an meat based diet for the bear after its recovery ? Give reason for your answer.

3

16. (a)

(i) (ii)

(b)

(a) Name the part of brain which controls (i) voluntary action, (ii) involuntary action. (b) What is the significance of the peripheral nervous system ? Name the components of this nervous system and distinguish between the origin

3

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of the two.

17.

Describe an activity to illustrate the phenomenon of phototropism and explain why does this occur.

3

18.

Draw schematic labeled diagram of box type solar cooker. Name two components of solar cooker which are responsible to increase the temperature inside the solar cooker. Explain their function.

3

19.

Explain geothermal energy. How can it be harnessed to produce electrical energy ?

3

20. (a) A B A B

(i) A B

(ii) A B

(b) Mg Cl2

Mg 12 Cl 17

(c)

(d)

(a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron. (i) What is the nature of bond between A and B ? (ii) Suggest the formula of the compound formed between A and B. (b) On similar lines explain the formation of Mg Cl2 molecule.

(c) Common salt conducts electricity only in the molten state. Why ? (d) Why is melting point of NaCl high ?

/ OR

(a) MgO Mg

(b)

(c)

(a) Carbon cannot be used as reducing agent to obtain Mg from MgO. Why ? (b) How is sodium obtained from molten sodium chloride ? Give equation of the reactions. (c) How is copper obtained from its sulphide ore ? Give equations of the

5

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reactions.

21. (a)

(b)

(c)

(a) Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this salt. Name the source from where it is obtained. (b) What is rock salt ? Mention its colour and the reason due to which it has this colour. (c) What happens when electricity is passed through brine ? Write the chemical equation for it.

/ OR

(a)

(b)

(c)

(a) Write the chemical name and chemical formula of washing soda. (b) How is it obtained from sodium chloride ? Give equations of the reactions. (c) Why it is called a basic salt ? Give its any one use.

5

22. (a)

(b) 220 V 5 A 176

(c)

(a) Calculate the resistance of the wire using the graph.

5

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(b) How many 176 resistors in parallel are required to carry 5A on a 220 V line ? (c) Define electric power. Derive relation between power, potential difference and resistance.

/ OR

(a) R1, R2, R3

(b)

(c) 5 A

(a) Three resistors R1, R2 and R3 are connected in parallel and the

combination is connected to battery, ammeter, voltmeter and key. Draw suitable circuit diagram. Obtain an expression for the effective resistance of the combination of resistors in parallel. (b) Why are electric bulbs filled with chemically inactive nitrogen or argon ? (c) What is meant by the statement that the rating of a fuse in a circuit is 5 A ?

23. (a)

(b) P S P

S

(i) P

(ii) P

(iii) P

(a) Define electromagnetic induction ? (b) Two coils P and S are wound over the same iron core. Coil P is connected to battery and key and the coil S is connected to galvanometer. Draw a suitable diagram of this arrangement and write your observations when : (i) Current in the coil P is started by closing the key. (ii) Current continues to flow in coil P. (iii) Current in coil P is stopped by removing the key. Explain the reason for such observations.

5

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/ OR

(a)

(b)

(c)

(a) Draw magnetic field lines around bar magnet. (b) Explain any two properties of magnetic field lines. (c) A current through a horizontal power line flows in east to west direction. What is the direction of magnetic field at a point directly below it ? State the rule which is used to find the direction of magnetic field in this case.

24.

(a)

(b)

(c)

Draw the diagram of sectional view of human heart and on it name and label the following parts : (a) The chamber of the heart that pumps out de-oxygenated blood. (b) The blood vessel that carries away oxygenated blood from the heart. (c) The blood vessel that receives de-oxygenated blood from the lower part of our body.

/ OR

(a)

(b)

(a) Draw the human respiratory system and label the following – lung, bronchi, alveolar. (b) During breathing cycle what is the advantage of residual volume of air in lungs ? Explain.

5

/ SECTION - B

25.

(a) (b) (c) (d)

When ferrous sulphate crystals are heated, the colour of the residue formed is : (a) red (b) brown (c) orange (d) green

1

26.

(a)

(b)

(c)

1

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(d)

A small amount of quick lime is taken in a beaker. Water is added slowly to the beaker. Which of the following observations were noted ? (a) Hissing sound and the solution becomes hot (b) No characteristic sound and solution turns cold (c) Hissing sound and the solution becomes cold. (d) No characteristic sound and the solution becomes hot.

27. pH

(a) NaOH (b)

(c) HCl (d) NaHCO3

The colour of pH strip turned red when it was dipped in a sample. The sample could be : (a) dilute NaOH solution (b) tap water (c) dilute HCl solution (d) dilute NaHCO3 solution

1

28. pH

(a) pH

(b) pH

(c) pH

(d) pH

The correct method of finding pH of solution is to : (a) heat the solution in the test tube and expose the pH paper to the vapours formed. (b) pour solution from the test tube on pH paper (c) drop the pH paper into the solution (d) add a drop of solution on the pH paper using a dropper.

1

29. I II 10 mL HCl 10 mL NaOH

(a)

(b) I II

(c) II I

(d)

10 mL of HCl and 10 mL of NaOH solutions are taken in two separate beakers labelled I and II respectively. On adding Zinc granules to both, it is observed that at room temperature (a) Gas is evolved vigorously in both (b) Gas is evolved vigorously in beaker I and not in the beaker II (c) Gas is evolved vigorously in beaker II but not in the beaker I (d) No gas is evolved in either of the two beakers

1

30. 15

(a) (b)

(c) (d)

1

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A new iron nail is placed in a beaker containing aqueous copper sulphate solution. When the nail is taken out after 15 minutes, its surface is coated with (a) reddish deposit (b) greenish deposit (c) black deposit (d) white deposit

31.

(a) (b)

(c) (d)

A piece of granulated Zn was dropped into copper sulphate solution. After some time the colour of solution changed from (a) light green to blue (b) blue to colourless (c) light green to colourless (d) blue to green

1

32. 2A 10 5 V 20

8

8

(a) 1.25 (b) 2 (c) 0.75 (d) 1.5 The number of division in ammeter of range 2A is 10 and voltmeter of range 5 V is 20. When the switch of the circuit given below is closed, ammeter reading is at 8th division and voltmeter reading is at 8th divisions. The value of resistance of resistor is –

(a) 1.25 (b) 2 (c) 0.75 (d) 1.5

1

33. /

(a) (b)

(c) (d)

1

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In Ohm’s law experiment, the physical quantity/quantities which is/are to kept constant while doing experiment is/are : (a) potential difference (b) current (c) temperature (d) potential difference, current, temperature

34. R1, R2 R1>R2

A, B, C

(a) R1, R2,

(b) R2, R1

(c) R2, R1,

(d) R1, R2

Ohm’s law experiment is performed separately with individual resistors R1, R2

[R1>R2] and series combination of R1, R2. Graph is plotted between potential

difference (V) and current (I) as shown in figure for each case : Identify which one is for R1, R2 and combination of resistors ?

In the graph A, B and C respectively represents

(a) R1, R2 and series combination

(b) series combination, R2, R1

(c) R2, R1 and series combination

(d) series combination, R1, R2

1

35.

/ /

(a) I, II (b) II, III (c) II (d) I

1

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Three students drew following circuit diagrams to find resistance of parallel combination of two resistors. Correct circuit diagram/diagrams are –

(a) I, II (b) II, III (c) II only (d) I only

36.

The circuit diagram shown below is used to find the effective resistance of two resistors in series. Which circuit diagram represents correctly ?

1

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37.

(a)

(b)

(c)

(d)

Other than light, which of the following are also essential for photosynthesis ? (a) carbon di-oxide, water, minerals, chlorophyll (b) carbon di-oxide, water, vitamins, chlorophyll (c) carbon, water, minerals, chlorophyll (d) carbon di-oxide, water, hormones, chlorophyll

1

38. 1

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(a) A (b) B (c) C (d) DWhich of the following set-up will give a positive result for starch test after boiling the leaf in alcohol ?

(a) A (b) B (c) C (d) D

39.

(a) (b) (c) (d)

The stomatal opening is controlled by guard cells. If the stomatal opening is to remain open how should the guard cells be ? (a) stretched (b) swollen (c) rigid (d) shrunk

1

40.

(a)

(b)

(c)

(d)

The guard cells are also capable of photosynthesis because they have : (a) cytoplasm, nucleus, centrioles (b) cytoplasm, nucleus, centrosome (c) cytoplasm, nucleus, chromosomes (d) cytoplasm, nucleus, chloroplasts

1

41.

(a)

(b)

(c)

1

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(d)

The gas released from germinating seeds indicate that the seeds are : (a) alive and decaying (b) alive and respiring (c) dead and decaying (d) alive and decomposing

42.

(a) CO2

(b) CO2

(c) CO2

(d) CO2 In the experimental set-up shown in the figure, water is found to rise in the delivery tube because :

(a) sodium hydroxide kept in the small test tube absorbs CO2

(b) calcium hydroxide kept in the small test tube absorbs CO2

(c) chromium hydroxide kept in the small test tube absorbs CO2

(d) potassium hydroxide in the small test tube absorbs CO2

1

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Page 1 of 7

MARKING SCHEME

SCIENCE

Class – X

SECTION-A

1. The angle between current carrying conductor and magnetic field is 90. 1

2. olfactory receptors, gustatory receptors 1

3. Solar panel ½+½=1

4. Fe2O32 Al Al2O32 Fe

Displacement reaction – One element displaces another element

1 ½ + ½

5. (a) sodium (b) iodine (c) gallium or caesium (d) lead or mercury

½x4=2

6. Energy consumed Pt 800 W 62430 3456 kW h

Cost 34.53 Rs 103.5

2

SC2-015 SUMMATIVE ASSESSMENT – I, 2012

Page 2 of 7

7.

Using compass needle. When we move away from the striaght wire the deflection of the needle decreases which implies the strength of the magnetic field decreases.

1

1

8. Metal is copper Black coloured substance is copper oxide

2 CuO2

2 CuO

CuOH2

CuH2O

½ ½ 1 1

9. (a) any suitable exothermic reaction (b) oxidising agent Cl2

Reducing agent H2S

(c) Rancidity , keeping in airtight containers

1 ½ ½

½+½

10. (a) Alkali NaOH (or) KOH

(b) Tooth decay starts when the pH of the mouth is lower than 5.5 It can be prevented by using tooth pastes which are generally basic (c) Bee-sting has acid that causes pain and irritation. Baking soda being alkaline neutralises acid and gives relief

½ ½ ½ ½

½+½

11. (a) Calcium starts floating when added to water because the bubbles of hydrogen gas formed stick to the surface of the metal and makes it

lighter (b) HNO3 is a strong oxidising agent. It oxidises H2 to H2O

(c) 3 Fe4 H2O Fe3O44 H2

Ferric oxide

1

1 ½

½

12. (a) (i) R L So resistance becomes two times i.e. R20

(ii) R 1/A 1/d2

So when diameter is doubled, resistance becomes ¼th of original i.e. R2.5

(b) Alloys do not oxidise readily at high temperature.

½ ½ ½ ½

1

Page 3 of 7

13.

RR1R2R330

IV/R30/301A

V across 10 I R211010 V

1

1 ½ ½

14. Current increases abruptly (i) When live wire and neutral wire in contact (ii) Accidental hike in the supply voltage (iii) Too many appliances connected to a single socket (Any two)

Or if a student give proper explanation of any two methods award 2 marks Should not connect too many appliance to the same socket or should avoid live and neutral wire contact by using proper insulation.

½

1+1

½

15. (a) Fig 6.5 with explanation (b) animal – based food, To digest plant – based food, the bear will need a

longer small intestine, for the cellulose to be digested.

2 1

16. (a) Voluntary actions – cerebellum; Involuntary action – medulla

(b) The communication between the central nervous system and the other parts of the body is facilitated by the peripheral nervous system.

Cranial nerves arise from the brain; spinal nerves arise from the spinal chord.

½ + ½ 1

½ + ½

17. Activity 7.2 Page 121 NCERT Text Book. When growing plants detect light, auxin ; synthesized at the shoot tip, helps the cells to grow longer; auxin always diffuses towards the shady side of the shoot; this concentrations of auxin stimulates the cells to grow longer on the side of the shoot which is

away from light; thus, the plant appears to bend towards light.

1 ½

1 ½

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18.

Plane mirror, glass sheet, painted black inside the cooker – any two

Plane mirror – maximise the amount of light entering the solar cooker Glass sheet – traps infra red radiation or produces green house effect Painted black – absorbs radiation

1

1

1

19. Due to geological changes, molten rocks formed in the deeper hot region of

earth’s crust are pushed upward and trapped in certain region – hot spots are formed. When underground water comes in contact with hotspots steam is generated.

The steam routed through pipe to a turbine and produce electricity.

1

1 1

20. (a) (i) Ionic bond (ii) AB2

2Mg M 2 eg2,8.2

2,8,7 2,8,8Cl e Cl

(b) NaCl is ionic compound, considerable energy is required to break

strong inter-ionic bonds. (c) Only in molten state it can split into ions and not in solid state. Ions

conduct electricity OR

(a) Mg has more affinity for oxygen than for carbon (b) Electrolytic reduction process

At cathode : 2 Na 2 e 2 Na

At anode : 2 Cl Cl2 2 e

(c) 2 Cu2S3 O2 2Cu2O 2 SO2

2 Cu2OCu2 S 6 CuSO2

½ + ½ ½x3=1½

½ ½ 1

½ ½ 1 1 ½ 1

½ 1

½ 1 1

21. (a) Hydrochloric acid and sodium hydroxide

NaCl, sodium chloride, Ocean water (b) Deposits of solid salt are found in several parts of the world. These

large crystals are called Rock salt.

½, ½ 3x½

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Brown, due to impurities

(c) 2 NaCl 2H2O Electricity

2NaOH Cl2H2

OR

Chemical name-sodium carbonate Formula – Na2CO3. 10 H2O

NaCl H2OCO2NH3 NH4ClNaHCO3

2 NaHCO3

Na2CO3CO2 H2O

Na2CO3 10 H2O Na2CO3 .10 H2O

It is a basic salt because when dissolves in water it gives a strong base NaOH In glass, paper industry As cleaning agent

For removing permanent hardness (any one)

½ ½, ½

½ ½

1 1

½ 1

½

22. (a) RV/I R2/0.120 (b) RV/I 220/5 44

Number of resistor is 176/44 4 (c) The rate at which electric energy is dissipated or consumed in an

electric circuit is called electric power

PV2/R OR

(a) Resistors in parallel circuit diagram II1I2I3 and explanation

I1V/R1 ; I2V/R2 ; I3V/R3 ; IV/RP

1/ RP 1/R11/R2 1/R3 with statement

(b) To prolong the life of filament. (c) That the maximum current that should flow in the circuit is 5 A. If it exceeds this, the fuse will be blown off.

½ ½ 1 1 1

1

1

2

½

1½

23. (a) Electromagnetic induction : The process by which a changing in magnetic field in a conductor induces a current in another conductor.

Diagram (b) (i) There is deflection in galvanometer connected with coils. due

to induced current. (ii) Deflection becomes zero. (iii) Deflection in galvanometer is in opposite direction. Reason :

(i) E.M. induction takes place because field is changing

(ii) Since current becomes stationary, no change in field takes place. So no EM induction.

(iii) EM. Induction takes place but induced current is in opposite direction.

OR

(a)

1

1

3x½=1½

3x½=1½

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(b) Any properties of magnetic field lines (i) No two lines of force ever intersect (ii) Relative strength of the magnetic field is shown degree of

closeness of the field lines, with explanation.

(c) South to North Correct statement of Fleming’s Right Hand Rule

1

1+1

1 1

24. Refer to NCERT text book fig. 6.10 (a) right ventricle (b) aorta (c) vena cava from lower body

(d) pulmonary veins. Correct name Correct label

OR

(a) Diagram To lable only lung, bronchi, ribs and alveolar sac

(Refer to NCERT text book figure 6.9) (b) so that there is sufficient time for oxygen to be absorbed and for CO2

to be released. The amount of water re-absorbed depends on how much excess water

is there in the body and how much of dissolved waste there is to be excreted.

2

3x ½ 3x ½

2 1

1

1

SECTION - B

25. (b) 1

26. (a) 1

27. (c) 1

28. (d) 1

29. (b) 1

30. (a) 1

31. (b) 1

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32. (a) 1

33. (c) 1

34. (d) 1

35. (c) 1

36. (c) 1

37. (a) 1

38. (b) 1

39. (b) 1

40. (d) 1

41. (b) 1

42. (d) 1

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