Set - A

• Please check that this question paper contains 7 printed pages.

• Code number given on the right hand side of the question paper should be

written on the title page of the answer-book by the candidate.

• Please check that this question paper contains 41 questions.

• Please write down the serial number of the question before attempting it.

SCIENCE (Theory)

General Instructions :

i) The question paper comprises of two sections A and B, you are to attempt both thesections.

ii) All questions are compulsory.iii) All questions of section A and all questions of section B are to be attempted

separately.iv) Question numbers 1 to 3 in section A are one mark question. These are to be

answered in one word or one sentence.v) Question numbers 4 to 7 are two mark questions, to be answered in about 30

words.vi) Question numbers 8 to 19 are three mark questions, to be answered in about 50

words.vii) Question numbers 20 to 24 are five mark questions, to be answered in about 70

words.viiii) 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 choose one mostappropriate response out of the four provided to you.

Time allowed : 3 hours Maximum Marks : 90

MT EDUCARE LTD.

Series RLH

Roll No. Code No. 32/1

SUMMATIVE ASSESSMENT - 12013-14 CBSE - X Set - A

Set - A... 2 ...

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SECTION - A

1. What should be the resistance of a Voltmeter?

2. Where do we find cerebrospinal fluid ? Give its function.

3. The main constituent of biogas is

4. What is an oxidation reaction ? Identify in the following reaction :i) the substance oxidized andii) the substance reduced

ZnO + C Zn + CO

5. A blue salt becomes white on heating. With the help of a reaction, explainthe change in colour.

6. A wire of length L and resistance R is stretched so that its length its doubled.How will its (a) Resistance change (b) Resistivity change?

7. What are the patterns of magnetic field lines inside and outside of asolenoid? What do they indicate?

8. In the reaction represented by following equation.

CuO (s) + H2(g) Cu (s) + H

2O (l)

a) Name the subsatance oxidised. b)Name the subsatance reduced.c) Name the oxidising agent. d)Name the reducing agent.

9. What are amphoteric oxides? Give equation.

10. a) What is corrosionb) Name any two metals which do not corrode easily.c) What is the corrosion of iron known as?

11. Name the substances oxidised and reduced, and also identify the oxidizingagents and reducing agents in the following reactions :i) Fe

2O

3 + 3CO Fe + 3CO

2

ii) 3MnO2 + 4Al 3Mn + 2Al

2O

3

iii) H2S + SO

2 S + H

2O

12. Explain the working of a thermal power plant.

13. Give characteristics of magnetic field lines. (Any three points 3 ×1=3 )

Set - A... 3 ...

3

3

3

3

3

3

5

14. A coil of insulated copper wire is connected to a galvanometer. What wouldhappen if a bar magnet is (i) Pushed into the coil? (ii) Withdrawn from insidethe coil? (iii) Held stationary inside the coil?

15. Which is the major nitrogenous waste product in a human being ? How isit removed from the body ?

16. (a) Why do the leaves of ‘Touch Me Not’ plant (Mimosa pudica) droop downwhen touched ?Name the phenomenon involved in such a response.

(b) Why does the flower of Dandelion opens up in the morning and closesin the eening ?Explain, Name this phenomenon.

17. Study the given diagram of the brain carefully and label the parts 1 to 6.

18. i) A current through a horizontal power line flows in north to southdirection. What is the direction of magnetic field(i) at a point directly below it and (ii) at a point directly above it?

ii) How can it be shown that magnetic field exists around a wire carryingcurrent?

iii) How can a solenoid be used to magnetize a steel bar.

19. A hot plate of an electic oven connected to a 220V line has two resistancecoils A and B, each of 24 resistance, which may be used (i) separately,(ii) in series or (iii) in parallel. What are the currents in the three cases ?

20. Classify the following equations into various type and also make thereactions more informative :(i) 4Na + O

2 2Na2O

(ii) ZnCO3 ZnO + CO

2

1

2

34

56

Set - A... 4 ...

(iii) BaCl2 + (NH

4) SO

4 BaSO4 + 2 NH

4Cl

(iv) Zn + 2Ag+ 2Ag + Zn2+

(v) Mg + dil. H2SO

4 MgSO4 + H

2

OR20. Effects of oxidation reactions in everyday life.

21. (a)(i) Name the metals which react vigorously and catch fire if kept

in the open.(ii) Name the type of oxide formed when magnesium is burnt in air ?(iii) What is aqua regia ?

(b) Explain how the following metals are obtained from their compoundsby the reduction process :(i) Metal M which is in the middle of the reactivity series.(ii) Metal N which is high up in the reactivity series.Give one example of each type.

OR(a) Distinguish between ‘roasting’ and ‘calcination’. Which of the two is

used for sulphide ores and why ?(b) How are the cracks in railway tracks joined.(c) Write the cathode, anode and electrolyte used in refining of copper.

22. What is the principle behind the working of electric generator? Explain itsworking with the help of well labeled diagram.

OR

(a) Derive an expression for the equivalent resistance of the combinationof two resistors connected in series.

(b) An electric bulb is marked 60 W. What does this mean ? How muchenergy does it consume if used for 1 hour ?

23. Explain the construction and working of electric motor?OR

(a) Explain an activity to show that a currentcarrying conductor experiences a forcewhen placed in a magnetic field.

(b) State the rule which gives the direction offorce acting on the conductor.

(c) An electron moves perpendicular to amagnetic field as shown in the figure.What would be the direction of forceexperienced on the electron ?

5

5

5

5

3

2

5

5electron

magnetic

field

Set - A... 5 ...

24. (a) Draw a diagram depicting Human Alimentary Canal and label on it,Gall Bladder, Liver, Small intestine and rectum Pancreas.

(b) State the roles of Liver and Pancreas.(c) Name the organ which performs the following functions in humans:

i) Absorption of digested food.ii) Absorption of water.

OR(a) Draw the structure of a neuron and label the following on it :

Nucleus, Dendrite, Cell body and Axon.(b) Name the part of neuron :

i) Where information is acquired.ii) through which information travels as an electrical impulse.

SECTION - B25. "Is malleable and ductile". This best describes:

(a) A metal (b) A compound(c) A non metal (d) A solution

26. An acidic oxide is produced by the element(a) Na (b) C(c) Ca (d) H

27. pH value less than 7 indicates that the solution(a) Acidic (b) Basic(c) Neutral (d) None of these

28. pH value greater than 7 indicates that the solution is(a) Acidic (b) Basic(c) Neutral (d) None of these

29. Pure water hasa pH value of(a) 3 (b) 4(c) 6 (d) 7

30. The pH value of hydrochloric acid is(a) 1.0 (b) 1.2(c) 2.0 (d) 2.3

31. The products of a burning candle are ......................(a) ash and water vapour (b) CO

2 and water vapour

(c) wax and water vapour (d) only melted wax.

32. The amount of work done in joules, when one unit electric charge movesfrom one point to another point in an electric circuit is called :(a) electric current (b) electric resistance(c) electric conductance (d) potential difference

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5

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Set - A... 6 ...

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33. The unit of potential difference is :(a) volt (b) ohm(c) ampere (d) faraday

34. The following circuit diagram shows the experimental set-up for the studyof dependence of current on potential difference. Which two circuitcomponents are connected in series.(a) Battery and voltmeter(b) Ammeter and voltmeter(c) Ammeter and rheostat(d) Resistor and voltmeter

35. In the experiment on finding the equivalent resistance of two resistorsconnected in series, three students connected the ammeter in theircircuits in the three ways, X, Y and Z shown here

(X) (Y) (Z)Assuming their ammeters to be ideal, the ammeter have been correctlyconnected in(a) Cases X and Y only (b) Cases Y and Z only(c) Cases Z and X only (d) All the three cases

36. The relation between potential difference (V) and current (I) is :(a) V I2 (b) V 1/I

(c) V2 I (d) V I

37. Stomata plays an important role in(a) respiration (b) photosynthesis.(c) transpiration (d) all the above

38. In the experiment to prove that light is necessary for, after boiling the leafin alcohol and washing it with water which of the following solution isadded to it ?(a) Saline solution (b) Starch solution(c) Sugar solution (d) Iodine solution

A

V

R

A

V V

A

V

A

Set - A... 7 ...

1

1

1

1

39. Which one of the following is correct set of three precautions for setting upthe experiment to demonstrate that is evolved during respiration ?(a) Air tight set up. delivery tube dips in water in beaker, flask has seeds

which have just germinated.(b) Thread holding KOH test the tube, air tight flask, delivery tube above

surface of water in the beaker.(c) Germinated seeds under water in the flask, experimental set up not

air tight, delivery tube above water level.(d) Delivery tube touching botton of water, KOH test tube held of by a thick

wire, seeds covered by water.

40. Students observed the epidermal peel of a leaf under the high power ofmicroscope. The following are the sketches made by them.

The correct sketch is(a) A (b) B(c) C (d) D

41. An object observed a slide of Yeastunder a microscope and saw collectionof cells in different parts of the slidemarked A, B, C and D as shown below.

Which one of the following parts of theslide shows budding in Yeast ?(a) A (b) B(c) C (d) D

42. To show that CO2 is released during respiration, we take:

(a) dry seeds (b) boiled seeds(c) wet seeds (d) germinating seeds

All the Best

Set - A

SECTION - A1. The resistance of a voltmeter should be very high and for an ideal voltmeter,

its value is infinity.

2. Cerebrospinal fluid is found between the meninges (membrances thatsurrounds the brain). This fluidprotects the brain from mechanical shocks.

3. methane

4. Oxidation reaction is one which involves gain of oxygen or loss of hydrogen.In the reaction ZnO + C Zn + COi) C is oxidized to COii) ZnO is reduced to Zn.

5. Copper sulphate crystals (CuSO4.5H

2O) are blue in colour. On heating, they

lose water of crystallization and turn white.

CuSO4.5H

2O

2

Heat-5H O CuSO

4

Hydrated copper AnhydrousSulphate Copper sulphate(Blue) (white)

6. (a) If the original length of the wire is l and its cross-sectional area is A,then R = l/A. When length becomes 2l, cross-sectional area reducesto A/2 becauseVolume does not change. The new resistance =(2l)/A/2=4 l/A = 4R

(b) Resistivity does not change.

7. (i) The field lines inside the solenoid are parallel straight lines. Thisindicates that the magnetic field is uniform and is therefore, same atall points inside it.

(ii) The field lines outside the solenoid are curved lines. This indicatesthat the magnetic field is non-uniform.

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MT EDUCARE LTD.CBSE X

Date :

SUBJECT : SCIENCE

SUMMATIVE ASSESSMENT - 1

MODEL ANSWER PAPER

Set - A

Marks : 90

Time : 3 hrs.

Set - A... 2 ...

8.

CuO + H2

Cu + H2O

This gives us the following conclusions about the above redox reaction :a) Substance oxidised : H

2

b) Substance reduced : CuOc) Oxidising agent : CuOd) Reducing agent : H

2

9. Some metal oxides, such as aluminium oxide, zinc oxide etc. Show both acidicas well as basic behaviour. Such metal oxides which react with both acids aswell as bases to produce salts and water are known as amphoteric oxides.Aluminium oxide reacts in the following manner with the acids and bases.Al

2O

3 + 6 HCl 2AlCl

3 + 3H

2O

Al2O

3 + 2NaOH 2NaAlO

2 + H

2O

10. a) The eating up of metals by the action of air, moisture or a chemical iscalled corrosion

b) Gold, Silver and Platinumc) Rusting

11. (i) Fe2O

3 + 3CO 2Fe + 3CO

2

Fe2O

3 is reduced because oxygen has been reduced and CO is oxidized

because O has been added to it.Fe

2O

3 has acted as oxidizing agent and CO has acted as reducing agent.

(ii) 3MnO2 + 4Al 3 Mn + 2Al

2O

3

MnO2 is reduced because O has been removed from it to give Mn. Al has

been oxidized because O has been added to it to obtained Al2O

3. MnO

2 is

the oxidizing agent while Al is reducing agent.

(iii) 2H2S + SO

2 3S + H

2O

H2S has lost H to change into S. thus, it has been oxidized. SO

2 has lost O to

change into S. Thus, it has been reduced. H2S has acted as reducing agent

while SO2 has acted as oxidizing agent.

12. A power plant in which the heat obtained by burning fossil fuels is used togenerate electricity is called thermal power plant. Coal is burnt in a furnaceto produce heat which boils the water to form steam. The steam at highpressure passes over the blades of the turbine making the turbine rotate.The shaft of the turbine is connected to a generator. Thus when the turbinerotates, its shaft rotates and the generator generates electricity.

3

3

3

1

1

1

3

Removal of oxygen

Addition of oxygen

Set - A... 3 ...

13. (i) They represent the magnetic field. (Any three points 3x1=3)(ii) They are directed from north to South Pole outside a magnet and from

south to North Pole inside a magnet.(iii) The field lines are closed curves.(iv) The strength of magnetic field in a region is determined by closeness

of the field lines in that region.(v) The closer the field lines are, greater will be the field strength and

vice-versa.(vi) No two field lines ever cross each other as it would mean two different

directions of field at point of intersection, which is not possible. (viii)The parallel lines represent the uniform magnetic field whereas

converging lines or diverging lines represents the non uniformmagnetic field.

14. (i) Due to change in magnetic flux linked with coil, the galvanometershows deflection (say towards right).

(ii) Due to change in magnetic flux linked with coil, the galvanometershows deflection (say towards left opposite to that in case one).

(iii) As it is stationary no change in magnetic flux linked with coil, sogalvanometer shows no deflection.

15. The major nitrogenous waste product in a human being is urea. It isremoved from the blood by filtration into Bowman’s capsule. The filtratecarrying urea passes from nephrons into a space inside kidney leading tothe ureter. From ureter, urea along with urine passes into the urinarybladder and is stored there till thrown out of the body.

16. (a) Movement in ‘Touch Me Not’ plant occur in response to touch (shock).In such movements, plant cells change shape by changing the amountof water in them (turgor changes) resulting in folding up and droopingof leaves. This phenomenon is called thigmonasty.

(b) Dandelion flower responds to light and reveals non-directionalmovemens called photonasticmovements. In bright light in the morning,it opens up and in the evening when light fades, it closes. Thisphenomenon is called photonasty.

17. 1. Cerebrum 2. Mid brain3. Cerebellum 4. Medulla5. Pons 6. Hypothalamus.

18. i) (i) West to East (ii) East to Westii) By using magnetic compass which, shows deflection.iii) By inserting the steel bar inside the solenoid and switching on electric

current.

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1

3

3

3

3

Set - A... 4 ...

3

5

5

19. (i) When the two coils A and B are used separately,R = 24, V = 220 V

Current, I = V

R =

220V

24= 9.167A.

(ii) When the two coils are connected in series,R = 24 + 24 = 48, V = 220 V

Current, I = V

R =

220

48= 4.58A.

(iii) When the two coils are connected in parallel,

R =24 24

24 24

= 12, V = 220 V

Current, I = V

R =

220

12= 18.33A.

20. (i) 4Na(s) + O2

(g) 2Na

2O(s) : Combination

(ii) ZnCO3 Heat ZnO (s) + CO

2 (g) : decomposition

(iii) BaCl2 + (NH

4) SO

4 BaSO4 (s) + 2 NH

4Cl(aq) : Double

decomposition

(iv) Zn(s) + 2Ag+ (aq) Zn2 + 2Ag(s) : Displacement reaction it canalso be termed redox reaction where Zn is oxidized to Zn2+ and Ag+ isreduced to Ag.

(v) Mg (s) + dil. H2SO

4 (aq) MgSO

4 (aq) + H

2 (g) : Single Displacement

OR

20. Oxidation has damaging effect on metals as well as on food. The damaging effect of oxidation on metals is studied as corrosion and

that on food is studied as rancidity.

Corrosion Corrosion is the process in which metals are attacked gradually, by substances

around it such as action of air, moisture or a chemical (such as an acid) ontheir surface.

Iron gets coated by a reddish brown powder as a result of rusting (corrosion)The black coating on silver and the green coating on copper are other examplesof corrosion.

Corrosion causes damage to car bodies, bridges, iron railings, ships andto all objects made of metals, specially those of iron.

Rancidity The condition produced by oxidation of fats and oils in foods marked by

unpleasant smell and taste is called rancidity.

Set - A... 5 ...

5

The development of rancidity of food can be prevented or retarded ( sloweddown) in the following ways :a) Rancidity can be prevented by adding antioxidants to foods containing

fats and oils. Antioxidants are chemicals which prevents oxidation.The two common anti-oxidants used in foods are BHA (Butylatedhydroxyl-anisole) and BHT (Butylated Hydroxy Toluene).

b) Rancidity can be prevented by packaging fat and oil containing foodsin nitrogen gas. The manufacturers of potato chips (and other similarfood products) fill the plastic bags containing chips with nitrogen gas.

c) Rancidity can be retarded by storing food in air-tight containers.

d) Rancidity can be retarded by keeping food in a refrigerator.

e) Rancidity can be retarded by storing foods away from light.

21.(a) (i) Sodium and potassium.

(ii) Basic oxide.

(iii) It is a freshly prepared mixture of concentrated hydrochloric acid andconcentrated nitric acid in the ratio of 3 : 1. It can dissolve gold andplatinum.

(b) (i) Metals which are in the middle of reactivity series are moderatelyreactive. These are usually present as sulphides or carbonates innature. It is easier to obtain metal from its oxide, as compared to itssulphides and carbonates. Therefore, prior to reduction, the metalsulphides and carbonates must be converted into metal oxides. Themetal oxides are reduced to the corresponding metals by usingreducing agents such as carbon. For example, when zinc oxide is heatedwith carbon, it is reduced to zinc.

ZnO(s) + C(s) Zn(s) + CO(g)

(ii) Metals that are high up in the reactivity series are very reactive. Theycannot be obtained by heating with carbon. For example, carbon reducethe oxides of sodium, magnesium, cacium, aluminium, et,. To therespective metals. This is because these metals have greater affinityfor oxygen than carbon. These metals are obtained by the electrolyticreduction. For example, sodium, magnesium and calcium are obtainedby the electrolysis of their molten chlorides. Aluminium is obtainedby the electrolytic reduction of aluminium oxide.

Set - A... 6 ...

5

3

Or

(a) Sulphide ores are converted into oxides by heating strongly in the presenceof excess air. This process is known as roasting.The carbonate ores are changed into oxide by heating strongly in limitedair. This process is known as calcinations.The chemical reaction that takes place during roasting and calcinationsof zinc ores can be shown as follows :Roasting :

2ZnS(s) + 3O2(g) Heat 2ZnO(s) + 2SO2(g)

Calcination :ZnCO

3(s) Heat ZnO(s)+ CO

2(g)

We use roasting for sulphide ores because excess air is required forcomplete oxidation to the metal oxide and sulphur dioxide.

(b) Use of aluminium for joining cracked railway lines is shown by the followingequation :

Fe2O

3(s) + 2Al(s) Heat 2Fe(l) + Al

2O

3(s) + Heat

Heat evolved in the reaction provides iron in the molten state which canbe used to join cracked railway lines.

(c) Cathode, anode and electrolyte used in the refining of impure copper aregiven below :Cathode : A thin strip of pure copper.Anode : Impure copper.Electrolyte : Acidified copper sulphate solution.

22. Principle of working (Electric generator): The electric generator works onthe principle that when a conductor is moved in a magnetic field thencurrent is induced in the conductor. The direction of the induced currentis given by Fleming's left hand rule.Construction and Working: The construction of a simple electric generatoris shown in the figure below:It has a rectangular coil which is placed between two strong horse-shoemagnets. On the periphery of coil large turns of insulated copper wire iswound.

Set - A

Here the ends A and D of the coil are connected to slip rings R1 and R2.They rotate along with the coil, while two carbon brushes B1 and B2 keepcontact with them.Suppose coil starts rotating in the clockwise direction than current isinduced in the coil, which flows from points ABCD. The direction of currentis given according to the Flemings left hand rule.After half rotation of the coil, arm CD starts moving up while AB startsmoving down. Now the flow current induced is reversed, that is currentflows through DCBA. Hence we may say that after every half cycle directionof flow of current is reversed. Because of this reason the current producedby the generator is also called as alternating current.

OR(a) Two resistors of resistances R± and R2 are connected in series. Let I

be the current through the circuit. The current through each resistoris also I. The two resistors joined in series is replaced by an equivalentsingle resistor of resistance R such that the potential difference V acrossit, and the current I through the circuit remains same.

V = IR

V1 = IR, V2 = IR2

IR = IR1 + IR2

IR = I (R1 + R2)

R = R1 + R2

(b) This means that 60 J of energy is used per secondEnergy = P x t

= 60 x 1h= 60 W-h= 0.06 kWh

2

5

5

+ -V

+

+

I

A

R1 R2

K

I

YX

Coil

CarbonBrush

Galvalometer

SlipRings

... 7 ...

Set - A

23. Construction: An ordinary electric motor consists of an armature ABCD (acoil of large number of turns) wound on an iron core. The armature isplaced in a strong magnetic field. The ends of the armature are connectedto two halves (P and Q) of a split ring. In electric motors, the split ring actsas a commutator (a device that reverses the direction of flow of currentthrough a circuit is called commutator). P and Q are in contact with carbonbrushes X and Y, respectively. The carbon brushes are then connected toa battery and a key.

Working: As soon as the key is closed, the current in arm AB of the coilflows from A to B and the current in arm CD flows from C to D. According toFleming's Left-Hand Rule, the arm AB will move downwards while the armCD will move upwards, resulting in the anticlockwise movement of thearmature along with the split ring. As soon as the armature ABCD reachesits vertical position while rotating, the current through the coil is cut off asthe brushes (X and Y) touch the gap between P and Q. The coil does notstop rotating as it has gained momentum and it goes beyond the verticalposition. When coil goes beyond vertical position, the direction of currentalong the arms AB and CD is reversed .Therefore, the direction of forceacting on AB and CD gets reversed. Now, AB moves up and CD goes down.Again, due to momentum, the armature continues its anticlockwiserotation. Finally, the coil reaches its initial position. The cycle continuesas long as there is flow of electric current through the armature. An axlecan be attached to the rotating split ring which can be used to do work.

OR(a) A small aluminium rod suspended horizontally from a stand using

two connecting wires. Place a strong horseshoe magnet in such a waythat the rod lies between the two poles with the magnetic field directedupward. For this put the north pole of the magnet vertically below andsouth pole vertically above the aluminium rod. Connect the aluminiumrod in series with a battery, a key and a rheostat. Pass a current throughthe aluminium rod from one end to other (B to A). The rod is displacedtowards left. When the direction of current flowing through the rod isreversed, the displacement of rod accross towards right.

5

5

... 8 ...

Set - A

(b) Flemings left hand rule. Stretch thethumb, fore finger and middle finger ofyour left hand such that they aremutually perpendicular. If the forefinger points in the direction ofmagnetic field and the middle finger inthe direction of current, then the thumbwill point in the direction of motion orthe force acting on the conductor.

(c) Perpendicular to the plane of the paperoutwards.

24. (a)

(b) Liver secretes bile juice which helps in digestion of fats.Pancreas secretes pancreatic juice which contains enzymes liketrypsin for digesting proteins and lipase for breaking down emulsifiedfats.

(c) i) Small intestine.ii) Large intestine.

OR(a) The diagram ofa neuron is given below:

5

5

mouth

salivary glands

esophagus

stomachpancreas

small intestine

rectum

large intestine

GallbladderDuodenum

liver

... 9 ...

Set - A

(b) The part of neuron:(i) Information is acquired at the end of the dendritic tip of a nerve

cell.(ii) The information travels as an electrical mpulse from the dendrite

to the cell body and then along the axon to its end.

SECTION - B

25. (a) A metal

26. (b) C

27. (a) Acidic

28. (b) Basic

29. (d) 7

30. (a) 1.0

31. (b) CO2 and water vapour

32. (d) potential difference

33. (a) volt

34. (c) Ammeter and rheostat

35. (c) Cases Z and X only

36. (d) V I

37. (d) all the above

38. (d) Iodine solution

39. (a) Air tight set up. delivery tube dips in water in beaker, flask has seedswhich have just germinated.

40. (b) B

41. (b) B

42. (d) germinating seeds

11111111111111

1111

NucleusMyelin sheath

cell(body)

Nerve end

Axon

Dendrites

... 10 ...