# Class 10 Science Sample Paper Solution - CBSE

1.Reema took 5ml of Lead Nitrate solution in a beaker and added approximately 4ml of Potassium Iodide solution to it. What would she observe?

A. The solution turned red.
B. Yellow precipitate was formed.
C. White precipitate was formed.
D. The reaction mixture became hot.

2. Identify gas A in the following experiment.

A. Nitrogen
B. Hydrogen
C. Oxygen
D. Carbon dioxide

3.Which of the following two combinations are correct?

 Option Metal Gas Evolved (i) Copper Yes (ii) Iron Yes (iii) Magnesium No (iv) Zinc Yes
A. i and iii
B. i and iv
C. ii and iii
D. ii and iv

4. Which of the following correctly represents a balanced chemical equation?

A. Fe(s) + 4"H"_{2}O(g) → F"e"_{3}"O"_{4} (s) + 4"H"_{2}(g)
B. 3Fe(s) + 4"H"_{2}O(g) → F"e"_{3}"O"_{4} (s) + 4"H"_{2}(g)
C. 3Fe(s) +
"H"_{2}O(g) → F"e"_{3}"O"_{4} (s) + "H"_{2}(g)
D. 3Fe(s) + 4
"H"_{2}O(g) → F"e"_{3}"O"_{4} (s) + "H"_{2}(g)

5. The graph given below depicts a neutralization reaction (acid + alkali → salt + water).
The pH of a solution changes as we add excess of acid to an alkali.

Which letter denotes the area of the graph where both acid and salt are present?

A. A
B. B
C. C
D. D

6. In the reaction of iron with copper sulphate solution:
CuS"O"_{4} + Fe ---> Cu + FeS"O"_{4}

 Option Metal Gas Evolved (i) Fe Fe (ii) Fe CuS”O”_{4} (iii) Cu Fe (iv) CuS”O”_{4} Fe

7. The chemical reaction between copper and oxygen can be categorized as:

A. Displacement reaction
B. Decomposition reaction
C. Combination reaction
D. Double displacement reaction

8. Which of the given options correctly represents theParent acid and base of Calcium Carbonate?

 Option PARENT ACID PARENT BASE (i) HCI NaOH (ii) "H"_{2}"C"O"_{3} Ca(O"H")_{4} (iii) "H"_{3}"P"O"_{3} CaS"O"_{4} (iv) CuS"O"_{4} CaS"O"_{4}

9. How will you protect yourself from the heat generated while diluting a concentrated acid?

A. By adding acid to water with constant stirring.
B. By adding water to acid with constant stirring.
C. By adding water to acid followed by base.
D. By adding base to acid with constant stirring.

10.Why is it important to balance a skeletal chemical equation?

A. To verify law of conservation of energy.
B. To verify the law of constant proportion.
C. To verify the law of conservation of mass.
D. To verify the l0aw of conservation of momentum

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11. Carefully study the diagram of the human respiratory system with labels A, B, C and D. Select the option which gives correct identification and main function and /or characteristic.
A. (i) Trachea: It is supported by bony rings for conducting inspired air.
B. (ii) Ribs: When we breathe out, ribs are lifted.
C. (iii) Alveoli: Thin-walled sac like structures for exchange of gases.
D. (iv) Diaphragm: It is pulled up when we breathe in.

12. Identify the option that indicates the correct enzyme that is secreted in location A, B and C.

A. (i)-lipase, (ii)-trypsin, (iii)-pepsin
B. (i)-amylase, (ii)-pepsin, (iii)-trypsin
C. (i)-trypsin, (ii)-amylase, (iii)-carboxylase
D. (i)-permease, (ii)-carboxylase, (iii)-oxidase

13. Opening and closing of stomatal pore depends on:

A. Atmospheric temperature
B. oxygen concentration around stomata
C. carbon dioxide concentration around stomata
D. water content in the guard cells

14. The figure given below shows a schematic plan of blood circulation in humans with labels (i) to (iv). Identify the correct label with its functions?

A. (i) Pulmonary vein - takes impure blood from body part.
B. (ii) Pulmonary artery - takes blood from lung to heart.
C. (iii) Aorta - takes blood from heart to body parts.
D. (iv) Vena cava takes - blood from body parts to right auricle.

15. Identify the phase of circulation which is represented in the diagram of heart given below. Arrows indicate contraction of the chambers shown.

A. Blood transferred to the right ventricle and left ventricle simultaneously.
B. Blood is transferred to lungs for oxygenation and is pumped into various organs simultaneously.
C. Blood transferred to the right auricle and left auricle simultaneously.
D. Blood is received from lungs after oxygenation and is received from various organs of the body.

16. Observe the diagram of Human digestive system.

Match the labeling referred in column I and correlate with the function in column II.

 column I column II i a. The lenthof this depends on food the organism eats. ii b. Initial phase of starch digestion. iii c. Increase the efficiency of lipase enzyme action. iv d. This is site of the complete digestion of carbohydrates, proteins and fats.
A. i.- a) ; ii – b) ; iii – c) ; iv- d)
B. i.- b) ; ii – c) ; iii – d) ; iv- a)
C. i.- b) ; ii – d) ; iii – c) ; iv- a)
D. i.- d) ; ii – a) ; iii – b) ; iv- c)

17. Which of the following mirror is used by a dentist to examine a small cavity in a patient’s teeth?

A. Convex mirror
B. Plane mirror
C. Concave mirror
D. Any spherical mirror

18. Which diagram shows image formation of an object on a screen by a converging lens?

19. Which of the following can make a parallel beam of light when light from a point source is incident on it?

A. Concave mirror as well as convex lens.
B. Convex mirror as well as concave lens.
C. Two plane mirrors placed at 90° to each others.
D. Concave mirror as well as concave lens.

20. Consider these indices of refraction: glass: 1.52; air: 1.0003; water: 1.333. Based on the refractive indices of three materials, arrange the speed of light through them in decreasing order.

A. The speed of light in water > the speed of light in air > the speed of light in glass.

B. The speed of light in glass > the speed of light in water > the speed of light in air.

C. The speed of light in air > the speed of light in water > the speed of light in glass.

D. The speed of light in glass > the speed of light in air > the speed of light in water.

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21. If a beam of red light and a beam of violet light are incident at the same angle on the inclined surface of a prism from air medium and produce angles of refraction r and v respectively, which of the following is correct?

A. r = v
B. r > v
C. r = 1/v
D. r < v

22.

Examine the above figure and state which of the following option is correct? [one small box in the figure is equal to 1 cm]

A. The mirror has a focal length of -6 cm and will produce an image of magnification +1.
B. The mirror has a focal length of -3 cm and will produce an image of magnification -1.
C. The mirror has a focal length of -3 cm and will produce an image of magnification +1.
D. The mirror has a focal length of -6 cm and will produce an image of magnification -1.

23.

The angle of incidence from air to glass at the point O on the hemispherical glass slab is.

A. 45°
B. 0°
C. 90°
D. 180°

A. (i)
B. (ii)
C. (iii)
D. (iv)

25.

Identify the correct option from the given table which represents the type of reactions occurring in step 1 and step 2

26. In which year is concentration of hydrogen ion the highest?
A. 2002
B. 2008
C. 2011
D. 2005

27. The diagram shows the reaction between metal and dil. acid.

What is the reason for different behaviour of Mg in test tube B?

A. Mg is lighter element than dil. HCl
B. Mg reacts with dil. HCl to produce H2 gas which helps in floating
C. Mg reacts with dil. HCl to produce N2 gas which helps in floating
D. Mg reacts with dil. HCl to produce CO2 gas which helps in floating

28. The table shown below gives information about four substances: A, B, C and D.

Identify Ionic compounds from the above given substances.

A. A, B
B. B, C
C. A, B, D
D. A, C, D

29. Vinay observed that the stain of curry on a white shirt becomes reddish-brown when soap is scrubbed on it, but it turns yellow again when the shirt is washed with plenty of water. What might be the reason for his observation?

i. Soap is acidic in nature
ii. Soap is basic in nature
iii. Turmeric is a natural indicator which gives reddish tinge in bases
iv. Turmeric is a natural indicator which gives reddish tinge in acids

A. i and ii
B. ii and iii
C. i and iv
D. ii and iv

30. In which of the following setups would the bulb glow?

A. i and ii
B. i and iv
C. ii, iii and iv
D. i, ii and iv

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Question No. 31 to 35 consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is False but R is true

31. Assertion: Fresh milk in which baking soda is added, takes a longer time to set as curd.

Reason: Baking soda decreases the pH value of fresh milk to below 6.

32. Assertion: Decomposition of vegetable matter into compost is an endothermic reaction.

Reason: Decomposition reaction involves breakdown of a single reactant into simpler products.

33. Assertion: Resins and gums are stored in old xylem tissue in plants.

Reason: Resins and gums facilitate transport of water molecules.

34. Assertion: Sky appears blue in the day time.

Reason: White light is composed of seven colours

35. The table given below shows the reaction of a few elements with acids and bases to evolve Hydrogen gas.

Which of these elements form amphoteric oxides?

A. A and D
B. B and D
C. A and C
D. B and D

36. In which of the following groups of organisms, blood flows through the heart only once during one cycle of passage through the body?

A. Rabbit, Parrot, Turtle
B. Frog, crocodile, Pigeon
C. Whale, Labeo, Penguin
D. Shark, dog fish, sting ray

37. What is common between extensive network of blood vessels around walls of alveoli and in glomerulus of nephron?

A. Thick walled arteries richly supplied with blood
B. Thin walled veins poorly supplied with blood
C. Thick walled capillaries poorly supplied with blood.
D. Thin walled capillaries richly supplied with blood

38. Plants use completely different process for excretion as compared to animals. Which one of the following processes is NOT followed by plants for excretion?

A. They can get rid of excess water by transpiration.
B. They selectively filter toxic substances through their leaves.
C. Waste products are stored as resins and gums in old xylem.
D. They excrete waste substances into the soil around them.

39. If the power of a lens is - 4.0 D, then it means that the lens is a

A. concave lens of focal length -50 m
B. convex lens of focal length +50 cm
C. concave lens of focal length -25 cm
D. convex lens of focal length -25 m

40. Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?

A. 30 cm in front of the mirror
B. 15 cm in front of the mirror
C. Between 15 cm and 30 cm in front of the mirror
D. More than 30 cm in front of the mirror

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41. In which of the following groups of organisms, food material is broken down outside the body and then absorbed in?

A. mushroom, green plants, amoeba
B. yeast, mushroom, bread mould
C. paramecium, amoeba, cuscuta
D. cuscuta, lice, tapeworm

42. In a person the tubule part of the nephron is not functioning at all. What will its effect be on urine formation?

A. The urine will not be formed.
B. Quality and quantity of urine is unaffected.
C. Urine is more concentrated.
D. Urine is more diluted.

43. If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle 14 be placed from the lens?

A. -80cm
B. -40 cm
C. -40/3 cm
D. -80/3 cm

44.

While looking at the above diagram, Nalini concluded the followingi. the image of the object will be a virtual one. ii. the reflected ray will travel along the same path as the incident ray but in opposite direction. iii. the image of the object will be inverted. iv. this is a concave mirror and hence the focal length will be negative. Which one of the above statements are correct?

A. i and ii
B. i and iii
C. ii, iii and iv
D. i, ii, iii and iv

45.

In the above diagram light is travelling through different media. It is noted by a scientist that ∠1= ∠3= ∠4 but ∠2 <∠1. Which of the following statement would be correct?

A. Medium 1 is the denser than medium 3 but it’s density is equal to medium 2.
B. Medium 2 is the rarest medium.
C. Medium 3 is denser than medium 1.
D. Medium 1 and 3 are essentially the same medium, but medium 2 is denser than 1 and 3.

46. The refractive index of flint glass is 1.65 and that for alcohol is 1.36 with respect to air. What is the refractive index of the flint glass with respect to alcohol ?

A. 0.82
B. 1.21
C. 1.11
D. 1.01.

47.

The above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.

A. 4 cm
B. 6.67 mm
C. 4 mm
D. 3.33 mm

48. A cable manufacturing unit tested few elements on the basisof their physical properties.

Which of the above elements were dicarded for usage by the company?

A. W, X, Y
B. X, Y, Z
C. W, X, Z
D. W, X, Z