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Latest Pattern Sample Paper {Science}

Term-I Examination (SA–I)

Time: 3 Hours Max. Marks: 90

1. When n resistors of equal resistance R each are connected in series, what

will be the equivalent resistance?

Solution: When n resistors of equal resistance R each are connected in series, the

equivalent resistance becomes nR.

2. Why should the key be taken out after taking the readings?

Solution: The key should be taken out after taking the reading to

(i) avoid heating of resistor wire,

(ii) avoid change in resistivity of wire.

3. What is the SI unit of potential difference?

Solution: SI unit of potential difference is volt.

General Instructions:

(i) The question paper comprises of 36 questions.

(ii) All questions are compulsory.

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

questions of five marks category.

Only one option in such questions is to be attempted.

(iv) Questions 1 to 12 are 1 mark questions. These are to be answered in one word or

in one sentence.

(v) Questions 13 to 18 are 2 marks questions. These are to be answered in about 30

words each.

(vi) Questions 19 to 30 are 3 marks questions. These are to be answered in about 50

words each.

(vii) Questions 31 to 36 are 5 marks questions. These are to be answered in about 70

words each.



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4. What is nuclear fusion?

Solution: Nuclear Fusion Reaction in which two or more small nuclei fuse to form a

heavy nucleus is called nuclear fusion, e.g., fusion of hydrogen.

5. Where does dark reaction of photosynthesis occur?

Solution: Dark reaction of photosynthesis occurs in stroma.

6. The leaf of a destarched plant is covered with black paper strip. After 8 h, starch test is

done. In which part will the colour be blue-black?

Solution: In 'A' part, the colour will be blue-black. It is because, photosynthesis

occurred at uncovered portion results in the formation of starch which gives blue-black

colour with starch test i.e., iodine solution.

7. Name the process by which roots absorb water from soil.

Solution: Osmosis is the process by which roots absorb water from soil.

8. Why is tungsten metal selected for making filaments of incandescent lamp bulb?

Solution: Tungsten has a high melting point. Therefore, it is used for making filament of

bulbs.

9. Which is the largest gland of our body and what is its function?

Solution: Liver is the largest gland of our body and it secretes bile juice for digestion of

fat.

10. Compare the pH of oxalic acid with seven.

Solution: The pH of oxalic acid is less than seven.

11. A blue litmus paper was first dipped in dil. HCl and then in dil. NaOH solution. What

change in colour of litmus paper you will observe?

Solution: A blue litmus paper was first dipped in dil. HCl and then in dil. NaOH solution.



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The colour of litmus paper became first red and then blue.

12. When zinc granules are kept in copper sulphate solution, what change in colour of

solution you will observe?

Solution: When zinc granules are kept in copper sulphate solution, the colour of

solution becomes colourless due to the formation of ZnSO4

Zn(s)+CuSO4(aq) ZnSO4 (aq)+Cu(s)

Colourless

13. (a) When do we put the resistance in series combination?

(b) How will you find the equivalent resistance of two resistors when they are

connected in series?

Solution: (a) When we have the smaller value of resistance and need the greater value

of resistance, we put them in series combination.

(b) The equivalent resistance of two resistors R1 and R2 is determined by

Rs = R1 + R2

14. (a) Four students were asked to test the pH of four samples as shown under. Whose

result is reported correctly?

Student H2O CH3COOH HCl NaOH

A 7 1 1 1

B 7 3 1 1

C 7 1 1 13

D 7 3 1 13

(b) Bottle A contains a dilute solution of vinegar and bottle B contains sodium carbonate

solution. Write the colour seen in pH paper dipped in A and B.

Solution: (a) TheresuItofstudentD.lt is because, water is neutral having pH = 7

CH3 COOH is a weak acid having pH = 3

HCl is a strong acid having pH = 1

NaOH is strong base having pH = 13

(b) In bottle A colour of pH paper is orange due to the presence of acid (vinegar).



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In bottle B colour of pH paper is blue due to the presence of base (sodium carbonate

solution).

15. (a) What is the colour of precipitate formed when, barium chloride reacts with sodium

sulphate solution?

(b) Name this type of reaction.

Solution: (a) A white precipitate of barium sulphate is formed when barium chloride

reacts with sodium sulphte solution.

BaCl2 +Na2SO BaSO4 +2NaCl

While ppt.

(b) It is double displacement as well as precipitation reaction.(Because two compounds

exchange their ions and one of the product formed is insoluble).

16. Which mechanism plays an important role in transportation of water in plants?

(a) During daytime (b) At night

Solution: (a) During daytime transpiration pull plays an important role.

(b) At night root pressure plays an important role.

17. In the figure given below

(a) Which type of movement is shown by the plant in above activity?

(b) The information below shows the function of the responses of plants

To gain mineral salts in the soil and to get support.

Name the response related with the functions above.

Solution: (a) Photo tropic movement is shown by the plant because its shoot bends in

the direction of light.

(b) At the above functions like, to gain mineral salts in the soil and to get support are



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done by roots. These roots grow towards the gravity. Therefore, the response related to

the above function is due to gravity i.e., positive geotropism.

18. Name the green dot-like structures in some cells observed by a student when a

leaf-peel was viewed under a microscope. What is this green colour due to?

Solution: The green dot-like structures are chloroplasts. This green colour is due to the

presence of a green pigment called chlorophyll. Chlorophyll is present in cell organelles

called chloroplast.

19. Write chemical formula for calcium oxy chloride. How is it prepared? What is its

common name? What is its use?

Solution: Chemical formula for Calcium oxychloride is CaOCl2. Its common name is

bleaching powder. It is prepared by the action of chlorine on dry slaked lime.

Ca(OH)2 + Cla CaOCl2 + H2O

It is used in paper industry to bleach wood pulp.

20. (a) A non-metal A which is the largest constituent of air, when heated with H2 in 1:3

ratio in the presence of catalyst (Fe) gives a gas B. On heating with O2 it gives an

oxide C. If this oxide is passed into water in the presence of air, it gives an acid D which

acts as a strong oxidising agent.

(a) Identify A, B, C and D.

(b) To which group of the Periodic Table does this non-metal belongs?

Solution: (a) A is nitrogen (N) (because in air, percentage of nitrogen is 78%). When it

reacts with H2, it forms NH3.

N2 + 3H2Fe 2NH3

(B)

Thus, B is ammonia (NH3). When it is heated with O2 it forms NO2.

N2 + 2O2 2NO2

(C)

C is NO2 (nitrogen dioxide). When it is passed into H2O, it forms HNO3. Thus, D is nitric

acid (HNO3).



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2NO2+H2O 2HNO3

(N) (D)

(b) The non-metal belongs to group 15 or VA.

21. Write chemical reaction for soda acid fire extinguisher. How does it work?

Solution: Chemical reaction for soda acid fire extinguisher is

3 2 4Sodium bicarbonate

2NaHCO H SO (dil)

2 4 2 2Sodium sulphate

Na SO 2H O 2CO

Working Released 2 gas does not support combustion. Being heavier than air, it cuts the

air supply to the burning object by covering it and hence fire gets extinguished due to

lack of oxygen.

22. How would you distinguish between baking soda and washing soda by heating?

Solution: On heating NaHCO3 (baking soda), (carbon dioxide) gas is given out that turns

lime water milky.

2NaHCO3 Heat Na2CO3+H2O + CO2

While on heating Na2CO3.10H2O (washing soda), water of crystallisation is given out and

the salt becomes anhydrous. The presence of water of crystallisation given as product

can be tested by treating it with anhydrous CuSO4 (white) which becomes blue in colour

hi its contact.

Na2CO3.10H2O Na2CO3 + 10H2O

23. An electric heater is rated at 2kW Calculate the cost of using it for 2 hours daily for

the month of September, if each unit costs Rs.4.00.

Solution: Electric energy consumed by heater in one day

= Power × Time

= 2kW×2h = 4kWh

Electric energy consumed by heater in one month

= 4 × 30 = 120 kWh [September = 30 days]

= 120 units [unit = 1 kWh]



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Cost of using the heater = 120 × 4.00 = Rs. 480.00

24. Define electric power. An electric motor takes 5 A from a 220 V line. Find the power of

the motor and energy consumed in 2 h.

Solution: The electrical energy consumed by a device per unit time is called electric

power.

Given, Current (I) = 5A,

Potential difference (V) = 220V,

Time (t) = 2h

Power of electric motor (P) = VI= 220 × 5

= 1100 w = 1.1 kw

Energy consumed by the motor = Pr=1.1 kW×2h

= 2.2 kWh

25. How does transpiration help in the functioning of plant? A plant leaf was coated with

vaseline. What happens to the leaf and why?

Solution: Transpiration is important in plant because

(i) It helps in ascent of sap through xylem.

(ii) It helps in removal of excessive water,

(iii) It helps in temperature regulation of plant.

Leaf does not remain healthy when coated with vaseline, because vaseline coat does not

allow gaseous exchange and transpiration from leaf surface.

26. (a) On what factors, the resistance of the conductor depends?

(b) What is (i) the highest, (ii) the lowest resistors that can be secured by combinations

of four coils of resistance 4 , 8 , 12 , 24 . ?

Solution: (a) Resistance of a conductor depends on the following factors

(i) Resistance of a conductor is directly proportional of the length of the conductor

(ii) Resistance of a conductor is inversely 'proportional to the area of cross-section.

(b) (i) The overall resistance is increased in a series combination.

Highest equivalent resistance



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= R1 + R2 + R3 + R4

= 4 + 8 + 12 + 24 = 48

(ii) The overall resistance is reduced in a parallel combination.

Lowest equivalent resistance

27. What are the functions of nervous system? Give two parts of vertebrate

nervous system.

Solution: Nervous system forms a network in the body for regulation, coordination and

control of activities

and functions of body.

There are two parts of vertebrate nervous system.

(i) Central Nervous System (CNS) includes spinal cord and brain.

(ii) Peripheral Nervous System (PNS) includes cranial nerves, visceral nerves and spinal

nerves.

28. A copper coil is connected to a galvanometer. What would happen if a bar magnet is

pushed into the coil with its North pole entering first? held at rest inside the coil? pulled

out again?

Solution: (a) When North pole is pushed into the coil, a momentary deflection is

observer in the galvanometer. This deflection indicates that a momentary current is

produced in the coil.

The direction of current in the coil is anti-clockwise.

(b) When the magnet is held at rest, there is no deflection in the galvanometer. It

indicates that no current is produced in the coil in this use.

(c) In pulling the magnet out of the coil, a deflection in opposite direction is observed. It

indicates that the current produced in the coil is in opposite direction.

29. How is biogas produced? Why is it a better fuel than cow dung?

Solution: Biogas is produced from biomass when it decays in the absence of oxygen in

presence of bacteria in a biogas plant.

It is a better fuel than cow dung cake because



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(i) It is a clean fuel, produces no smoke residue,

(ii) It has high calorific value.

(iii) It helps in waste disposal, even the left over slurry is used as manure.

30. (a) An iron nail is kept in copper sulphate solution. What happens and why?

(b) A metal M does not liberate hydrogen from acids but reacts with oxygen to give a

black colour product. Identify M and black coloured product and also explain the

reaction of M with oxygen.

Solution: (a) If an iron nail is kept in CuSO4 solution, then iron nail gets brown coating

due to Cu deposition and the?

Solution turns greenish due to the formation of FeSO4

Fe(s)+CuSO4(aq) Cu(s)+FeSO4(aq)

It is because, Fe being more reactive than Cu, displaces Cu from CuSO4 solution.

(b) M is copper (Cu) as it is less reactive than hydrogen and gives black product, copper

oxide (CuO) with oxygen.

2M Blackcolour

2Cu O 2CuO

31. Balance the following chemical equations

(a)Fe+ H2O Fe3O4 + H2O

(b)Na+ H2O NaOH+ H2

(c)Na2CO3 + HCl NaCl + H2O+ CO2

(d)Pb (NO3)2 PbO+NO2 + O2

(e)Na2SO4 + BaCl2 BaSO4 + NaCl

OR

List six physical properties of acids. How do acids react with metals?

Solution: (a) 3Fe + 4H2O Fe3O4+4H2

(b) 2Na + 2H2O 2NaOH + H2

(c) Na2CO3+2HCl 2NaCl + H2O + CO2

(d) 2Pb(NO3 )2 2PbO + 4NO2 + O2



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(e) Na2SO4 + BaCl2 BaSO4 + 2NaCl

OR

Physical properties of adds are

(i) Acids have sour taste.

(ii) Acids conduct electricity in their aqueous solution.

(iii) Acids can change blue litmus red.

(iv) Acids can make phenolphthalein colourless,

(v) Acids change colour of methyl orange to red.

(vi) Acids also act on natural indicators to change their colour.

Dilute acids react with metals to liberate hydrogen gas. e.g.,

Zn(s) + H2SO4(aq) ZnSO4(aq)+ H2(g)

Metals which are less reactive than hydrogen cannot displace it and don't react with

acid. e.g., silver, copper, gold, etc.

32. Malini stores curd in a beautifully designed copper containers for a party

in the evening. The guests complain that curd has turned bitter. She gets

embarrassed and feels sorry. One of the guests told her why this happens, so

that she would careful next time.

(a) What suggestion would have been given by guest to Malini?

(b) List values of Malini.

(b) What values are shown by the guest?

OR

Manisha is experimenting with acids in the lab. She is suggested by Nisha to wear lab

coat and goggles which she ignores. The acid spills over her dress and burns her hand

too. Nisha immediately rescues her by providing first aid and takes her to medical room.

(a) Throw light on values of Nisha.

(b) What precautions should be taken, while working in laboratory?

(c) Give examples of some strong acids.

Solution: (a) He suggested her not to store curd in metal container as lactic acid present



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in curd forms salts with metal which taste bitter.

(b) Malini has a good aesthetic sense, generous, polite and courteous.

(c) The guest is intelligent, practical, sharing and convincing.

OR

(a) Nisha is caring, spontaneous, cautious and helpful.

(b)In lab, one should wear lab coat and goggles. No chemical should be touched or

tasted. Apparatus and materials should be handled with most care.

(c) Some strong acids are H2SO4, HCl, HNO3, etc.

33. Rohit's father told him that various pipes are responsible for transport of

blood in our body. But he thinks that these are of single type. Describe the

types of blood vessels present in our body. Explain the function of each to

help Rohit.

OR

Hemant says his grandmother that water and minerals are transported from root to leaf

in plant. To help his grandmother, explain the mechanism of water and minerals

transport in plant.

Solution: Three types of blood vessels are connected to form a closed system in human

body.

(i) Arteries These are wide, thick elastic walled vassels, which carry blood from heart

to all body parts. Arteries carry oxygenated blood except pulmonary artery, which

carries deoxygenated blood from heart to lungs.

(ii) Capillaries Arteries keep dividing further into smaller vessels and finally for the

smallest vessels called capillaries. These have permeable wall and exchange gases,

nutrients and waste products across the tissues.



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(iii) Veins The capillaries combine together to form thin walled vessels called veins.

Veins carry deoxygenated blood from body organs to the heart. Pulmonary vein carries

oxygenated blood from lungs to the heart.

OR

The mechanism of transport of water and minerals in plants is as follows

(i) The xylem forms an interconnected network of vascular tissues, which create a

continuous channel from root tracheids to all plant parts.

(ii) The cells of root hair hi contact with soil take up ions, which create an ion

concentration

gradient between root and soil.

(iii) The water flows into root from soil due to osmosis.

(iv) Stomata loose water to the surroundings through transpiration. This creates a

suction force, which pulls water upwards to heights.

(v) The steady movement of water into the root from the soil pushes water upwards.

34. (a) State the rule to determine the direction of a

(i) magnetic field produced around a straight conductor carrying-current.

(ii) force experienced by a current-carrying straight conductor placed in a magnetic

field.

(iii) current induced in a coil due to its rotation in magnetic field.

(b)How will the magnetic force get affected on

(i) doubling the magnitude of current?

(ii) reversing the direction of current flow?

OR

What are magnetic and non-magnetic substances? Give two examples of each. What

material is used to make permanent magnet? How can electric current be used to

magnetise a coil of wire?

Solution: (a) (i) Ampere's Right-Hand Thumb Rule If current is passing through a

conductor in the direction of thumb of the right hand, then, the direction of magnetic



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field is given by that of curvature of fingers.

(ii) Fleming's Left-Hand Rule If the forefinger, centre finger and thumb of left hand are

stretched mutually perpendicular are forefinger points hi the direction of magnetic

field, centre finger points in the direction of flow of electric current, then thumb points

in the direction of force acting on the conductor.

(iii) Fleming's Right-Hand Rule If the forefinger, centre finger and thumb of right hand

are stretched mutually perpendicular and forefinger points in direction of magnetic

field, thumb points in the direction of motion of conductor, then centre finger points in

the direction

of induced current.

(b) (i) On doubling the magnitude of the current, magnetic force gets doubled.

(ii) On reversing the direction of current, direction of force gets reversed.

OR

The substances, which get attracted by a magnet are magnetic substances, e.g., iron,

nickel.

The substances which are not attracted by magnet are non-magnetic substances, e.g.,

aluminium, copper.

Permanent magnets are made of an alloy of iron, nickel and chromium (alnico).

Nipermag is also

used to make permanent magnets. Electric current passing through a coil of wire

produces magnetic field in and around the coil in the similar manner as bar magnet.

35. An electric lamp has resistance 20 . and conductor of 4H resistance are connected in

series to 6 V battery. Find

(a) total resistance of circuit.

(b) current through each resistance.

(c) potential difference across each resistor. Draw circuit diagram also.

OR

(a) State energy conversion occurring in an electric motor.



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(b) On what principle does a motor work?

(c) Draw a diagram of electric motor.

(d) Give two uses of electric motor.

Solution: Given that,

Resistance,R1 = 20 , Resistance R2 = 4 , Voltage, V = 6V

(a) Total resistance,

R = R1 + R2 = 20 + 4 = 24 . (As they are connected in series)

(b)Total current, V 6V

I 0.25AR 24

As lamp and conductor both are connected in series, so current through both of them

will be same as the total current. Current through each resistor = 0.25 A

(c) Potential drop across resistor, R1 = V1 = IK1

= 0.25×20 = 5.0V Potential drop across resistor, R2 =V2 = IR2

= 0.25×4 = 1V

The circuit diagram is shown below

OR

(a) In electric motor, electrical energy is converted into mechanical energy.

(b) It works on principle that when a current carrying conductor is placed in magnetic

field, it experiences a force. In other words we can say that when a rectangular coil is

placed

in a magnetic field and current is passed through it, two equal and opposite forces (on

opposite side) act on the coil which rotates it continuously.



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(c) The diagram of electric motor is shown below

(d) Motors are used in electric fans, pumps, grinders, mixers, etc.

36. Mention advantages and disadvantages of producing hydro electricity by construction

of dams.

OR

Explain the difference between nuclear fusion and fission reactions with examples. Why

can't energy due to fusion be used to meet our day-to-day energy needs?

Solution:

Advantages and disadvantages of constructing dam for electricity generations are

S. No. Advantages Disadvantages

(i) Hydel power is renewable source,

A lot of plants, animals and their habitat get submerged in water.

(ii) Reservoirs help in development of fishing industry

The downstream land becomes less fertile, sometimes barren.

(iii) Water can be stored for irrigation and purification.

A large number of people are displaced, construction of dam requires huge capital investment.



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OR

The differences between nuclear fusion and fission are given below

S. No. Nuclear fusion Nuclear fission

(i) Smaller nuclei fuse to form Bigger nucleus

bigger nucleus. Splits to form two or more smaller nuclei.

(ii) High temperature and pressure are required to start reaction.

The nucleus needs to be bombarded with neutron.

(iii)

Heat produced is than that produced in higher nuclear fission.

e.g., 2 2 3 11 1 2 0H H H n Heat

e.g., 235 1 141 92 192 0 56 36 0U n Ba Kr 3n Heat

(iv) No radioactive byproducts are released.

Radioactive byproducts are released.

Nuclear fusion cannot be used to meet our daily demands because it generates

tremendously large amount of heat.

It also requires high temperature and pressure conditions to initiate the reaction.

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