Science Sample Paper Class X 2025-26

Sample Paper

Class X 2025-26 Science (086)

Time: 3 Hours | Max. Marks: 80

General Instructions:

1. This question paper consists of 39 questions in 3 sections. Section A is Biology, Section B is Chemistry and Section C is Physics.
2. 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

1. Which of the following represents the correct sequence of events in the nutrition of Amoeba?

• (a) Digestion \( \rightarrow \) Ingestion \( \rightarrow \) Absorption \( \rightarrow \) Assimilation \( \rightarrow \) Egestion
• (b) Ingestion \( \rightarrow \) Digestion \( \rightarrow \) Absorption \( \rightarrow \) Assimilation \( \rightarrow \) Egestion
• (c) Egestion \( \rightarrow \) Ingestion \( \rightarrow \) Digestion \( \rightarrow \) Absorption \( \rightarrow \) Assimilation
• (d) Ingestion \( \rightarrow \) Assimilation \( \rightarrow \) Digestion \( \rightarrow \) Absorption \( \rightarrow \) Egestion

2. The nerve impulse is the signal transmitted along a nerve fibre. What is the correct pathway for the flow of this impulse within a single neuron?

• (a) Axon terminal \( \rightarrow \) Cell body \( \rightarrow \) Dendrite
• (b) Cell body \( \rightarrow \) Axon \( \rightarrow \) Dendrite
• (c) Dendrite \( \rightarrow \) Cell body \( \rightarrow \) Axon terminal
• (d) Axon terminal \( \rightarrow \) Dendrite \( \rightarrow \) Cell body

3. There are various methods to prevent pregnancy. Which of the following contraceptive methods also provides protection from acquiring sexually transmitted diseases (STDs)?

• (a) Copper-T
• (b) Oral Pills
• (c) Condom
• (d) Tubectomy

4. In a classic Mendelian monohybrid cross, when a heterozygous tall pea plant (Tt) from the F1 generation is self-pollinated, what is the resulting phenotypic ratio of tall to dwarf plants in the F2 generation?

• (a) 1:1
• (b) 1:2
• (c) 3:1
• (d) 2:1

5. In any ecosystem, certain organisms are responsible for breaking down complex organic substances from dead plants and animals into simpler inorganic substances. What are these essential organisms called?

• (a) Producers
• (b) Primary Consumers
• (c) Carnivores
• (d) Decomposers

6. Consider the following statements about the human heart:

• (i) The human heart is a four-chambered organ.
• (ii) The right ventricle pumps oxygenated blood to the lungs.
• (iii) The wall of the left ventricle is thicker than the wall of the right ventricle.
• (iv) Valves ensure that blood flows in only one direction through the heart.

Which of the above statements are correct?

• (a) (i), (iii), and (iv)
• (b) (i) and (ii) only
• (c) (ii) and (iv) only
• (d) All are correct.

7. Fertilization in flowering plants is the fusion of male and female gametes. Where does this process typically take place?

• (a) On the surface of the stigma.
• (b) Inside the growing pollen tube.
• (c) Within the anther of the stamen.
• (d) Inside the ovule, which is located within the ovary.

8. Assertion (A): Abscisic acid is referred to as a “stress hormone” in plants.
Reason (R): The production of abscisic acid in plants stimulates the closure of stomata, which helps to reduce water loss during dry conditions.

• (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.

9. Assertion (A): All variations that arise in a species have an equal chance of survival.
Reason (R): Natural selection favors variations that provide a survival advantage in a particular environment.

• (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.

10. While plants generate oxygen during the day, they produce carbon dioxide at night. Justify this statement.

11. Attempt either option A or B.

A. How is the process of breathing different in aquatic organisms compared to terrestrial organisms? Explain why the rate of breathing in aquatic organisms is much faster.

OR

B. What is translocation in plants? Name the tissue responsible for it and the form in which the food is transported.

12. In a grassland ecosystem, the following organisms are present: Grass, Grasshopper, Hawk, Lizard, and Snake. Construct two distinct food chains from this ecosystem, each starting with the producer.

13. Draw a neat diagram of a reflex arc showing the pathway of a reflex action when a person accidentally touches a hot object. Label the key components involved.

14. In pea plants, a pure tall plant (TT) is crossed with a pure short plant (tt).

• (i) What is the phenotype and genotype of the F1 generation?
• (ii) If the F1 plants are self-pollinated, what will be the ratio of pure tall, hybrid tall, and dwarf plants obtained in the F2 generation? Show the cross.

15. A student had a meal containing rice and lentils (dal). Refer to the figure of the human alimentary canal to answer the following questions.

[Diagram of Human Alimentary canal with labels: L (Mouth), M (Oesophagus), N (Stomach), O (Small Intestine), P (Large Intestine)]

Attempt either subpart A or B.

A. Name the component in rice that is the primary source of energy. Where does its digestion begin and which enzyme is responsible?

OR

B. Lentils are a rich source of protein. Describe the process of protein digestion that occurs in the stomach (Part N) and the small intestine (Part O).

C. How is the small intestine (Part O) designed to maximize the absorption of digested food?

16. Attempt either option A or B

A. (i) A student observed a slice of bread with a cottony growth after leaving it in a moist, dark place. Identify the organism and its mode of reproduction.
(ii) Explain how this mode of reproduction helps the organism to survive unfavourable conditions.
(iii) State one key advantage of sexual reproduction over this method.

OR

B. (i) Draw a labelled diagram of the longitudinal section of a flower.
(ii) List any three changes that take place in a flower after fertilization which lead to the formation of fruit and seed.
(iii) What is the function of the sepals and petals in a flower?

SECTION-B

17. Which of the following equations represent redox reactions and what are the values for ‘p’ and ‘q’ in these equations?

Equation 1: \[ pAgCl(s) \xrightarrow{\text{Sunlight}} 2Ag(s) + Cl_2(g) \]

Equation 2: \[ Zn(s) + qHCl(aq) \rightarrow ZnCl_2(aq) + H_2(g) \]

• (a) Only equation 1 is a redox reaction, p = 1 and q = 2
• (b) Only equation 2 is a redox reaction, p = 2 and q = 1
• (c) Both equations 1 and 2 are redox reactions, p = 2 and q = 2
• (d) Neither equation is a redox reaction, p = 1 and q = 1

18. Four statements about the reactions of oxides are listed.

• I. Lead(II) oxide reacts with both dilute hydrochloric acid and aqueous sodium hydroxide.
• II. Magnesium oxide reacts with dilute hydrochloric acid but does not react with aqueous sodium hydroxide.
• III. Copper(II) oxide reacts with both dilute hydrochloric acid and aqueous sodium hydroxide.
• IV. Sodium oxide reacts with aqueous sodium hydroxide but not with dilute hydrochloric acid.

Which statements are correct?

• (a) I and III
• (b) I and II
• (c) II and IV
• (d) III and IV

19. A strip of zinc is added to a test tube containing aqueous ferrous sulphate, and a copper wire is added to another test tube containing aqueous zinc sulphate. Which of the following observations is correct?

• (a) The green solution in the first test tube turns colourless, and the second test tube remains colourless with no change.
• (b) There is no reaction in the first test tube, but the blue solution in the second test tube turns colourless.
• (c) A brown coating is observed on the zinc strip, and a grey coating is observed on the copper wire.
• (d) The solution in both test tubes turns black, and a gas is evolved.

20. What change would you observe if you put blue litmus paper and red litmus paper into a sample of soap solution?

	Colour change on Blue Litmus	Colour change on Red Litmus
a	No change	Turns blue
b	Turns red	No change
c	Turns red	Turns blue
d	No change	No change

21. Which of the following substances, when mixed with water, will result in a solution with the lowest pH value?

• (a) Milk of Magnesia
• (b) Human Blood
• (c) Gastric juice from the stomach
• (d) Pure Water

22. When dilute hydrochloric acid is added to solid sodium carbonate placed in a test tube, the observation is:

• (a) A reddish-brown gas is evolved.
• (b) The solution turns milky, and the test tube becomes hot.
• (c) Brisk effervescence is seen due to the evolution of a colourless, odourless gas.
• (d) A yellow precipitate is formed.

23. In the reaction of an aqueous solution of lead(II) nitrate with an aqueous solution of potassium iodide, the insoluble substance formed is:

• (a) \( KNO_3 \)
• (b) \( Pb(NO_3)_2 \)
• (c) \( KI \)
• (d) \( PbI_2 \)

24. Assertion (A): Soaps are not effective cleansing agents in hard water.
Reason (R): Soaps form insoluble precipitates (scum) on reaction with calcium and magnesium ions present in hard water.

• (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.

25. Answer the following:

(a) School bells are designed to be sonorous. Why are they made of metals like brass or bronze and not wood?
(b) Aluminium metal is highly malleable. How is this property utilized in the food industry?

26. Attempt either option A or B.

(A) An element ‘Y’ is the most abundant metal in the earth’s crust. It is extracted by the electrolytic reduction of its molten oxide. This metal readily forms a thin, tough, and non-porous oxide layer on its surface upon exposure to air.

• (i) Identify the element ‘Y’.
• (ii) Explain why electrolytic reduction is necessary for its extraction.
• (iii) Write the chemical equation for the reaction that takes place at the cathode during its electrolysis.

OR

(B) Galvanisation is a common method used to protect iron articles from rusting.

• (i) Name the metal used to provide the coating on iron during galvanisation.
• (ii) Explain how this coating prevents rusting, even when the coating is scratched and the iron is exposed.
• (iii) Suggest one other method apart from galvanisation and painting that can be used to prevent the rusting of iron.

27. A student sets up an apparatus for the reaction of zinc granules with dilute sulphuric acid as depicted.

[Diagram showing a test tube with zinc granules and dilute sulphuric acid. Gas bubbles pass through a delivery tube into soap solution, creating bubbles that burn with a 'pop' sound.]

(a) What would the student observe happening near the surface of the zinc granules?
(b) Name the gas evolved in this process. How can its presence be tested in the laboratory?
(c) If the student touches the bottom of the flask after the reaction starts, what change in temperature would be felt? Justify your answer.

28. A farmer found that the soil in his fields was very acidic with a pH of around 4.5, resulting in poor crop growth. An agricultural expert advised him to add either quick lime (calcium oxide), slaked lime (calcium hydroxide), or chalk (calcium carbonate) to the soil.

(a) Why is highly acidic soil detrimental to crop growth?
(b) Explain why the addition of any of the three suggested substances can improve the soil quality.
(c) Write a balanced chemical equation showing the neutralisation of soil acid (assume sulphuric acid, \( H_2SO_4 \)) with slaked lime.

OR

A baker prepared a cake batter and added baking soda. However, he forgot to add another key dry ingredient, causing the final cake to have a bitter, soapy taste.

(a) What crucial ingredient, usually found mixed with baking soda in ‘baking powder’, did he likely forget? Why is this ingredient necessary?
(b) What is the chemical name and formula of baking soda?
(c) Explain the role of baking soda in making the cake soft and spongy, and write the chemical equation for the reaction that occurs when it is heated.

29. Attempt either option A or B.

(A) An organic compound ‘A’ has the molecular formula \( C_2H_6O \) and is a common solvent and the active ingredient in alcoholic beverages. When ‘A’ is warmed with alkaline potassium permanganate solution, it gets converted to an organic acid ‘B’. When ‘A’ and ‘B’ are heated together in the presence of a few drops of concentrated sulphuric acid, a new compound ‘C’ with a fruity smell is formed.

• (a) Identify the compounds ‘A’, ‘B’, and ‘C’.
• (b) Write the balanced chemical equation for the conversion of ‘A’ to ‘B’.
• (c) What is the general name for the process of formation of ‘C’?
• (d) Draw the electron dot structure for compound ‘A’.
• (e) What is the role of concentrated sulphuric acid in the formation of ‘C’?

OR

(B) Carbon is an element that forms the basis for all life. It belongs to Group 14 of the periodic table and exhibits unique properties.

• (a) What is the valency of Carbon? Name the property of carbon which allows it to form long chains with itself.
• (b) Carbon exists in various forms with different physical properties but identical chemical properties. What are these different forms called? Name one hard and one soft crystalline form.
• (c) Draw the structure of the hard crystalline form you named in part (b).
• (d) What type of bonds are present in compounds of carbon? Give a reason why these compounds are generally poor conductors of electricity.
• (e) Write the name and draw the electron dot structure of the simplest compound formed between carbon and hydrogen.

SECTION-C

30. A student observed the reflection of light from different types of spherical mirrors and made the following statements:

• I. A concave mirror can form a magnified and real image of an object.
• II. A convex mirror can only form a virtual image of an object.
• III. The magnification produced by a concave mirror can be negative.

Choose from the following the correct option that lists the correct statements.

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

31. Choose the correct option from the below which explains the reason for us to perceive the day sky as blue.

• (a) As sunlight passes through the atmosphere, shorter wavelengths, such as blue are scattered more than other colors.
• (b) The sky appears blue because all colors are scattered equally, but blue light is stronger and more visible to the human eye.
• (c) The blue color of the sky is due to longer wavelengths like red and orange scattering more than shorter wavelengths, making blue stand out.
• (d) The atmosphere contains blue-colored particles that give the sky its blue appearance.

32. Assertion (A): A point object is placed at a distance of 26 cm from a convex mirror of focal length 26 cm. The image will not form at infinity.
Reason (R): For above given system the equation \( \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \) gives \( v = 3 \).

• (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.

33.

[Diagram showing a lens placed on an axis A.]

(A) Which type of the lens is used in the above diagram?
(B) Complete the diagram in your answer book.
(C) Write the nature of the image formed.

34. Attempt either option A or B.

A. Two identical resistors of \( 24\Omega \) each are connected to a battery of 6 V. Calculate the ratio of the power consumed by the resulting combinations with (a) Minimum resistance and (b) Maximum resistance.

OR

B. The current flowing through a resistor connected in a circuit and the potential difference developed across its ends are as shown in the diagram by milliammeter and voltmeter readings respectively:

(a) What are the least counts of these meters?
(b) What is the resistance of the resistor?

35. Study the diagram given below and answer the questions that follow:

[Diagram showing a defect of vision where light rays focus before reaching the retina.]

(i) Name the defect of vision represented in the diagram. Give reason for your answer.
(ii) List two causes of this defect.
(iii) With the help of a diagram show how this defect of vision is corrected.

36. A wire is cut into three equal parts and then connected in parallel. How will its:
(a) Resistance
(b) Resistivity get effected?

37. The magnetic field lines are shown around a current-carrying straight conductor. A student claims that the magnetic field strength at point P is stronger than at point Q.

[Diagram of concentric magnetic field circles around a straight wire. Point P is on the outer circle, Point Q is on an inner circle closer to the wire.]

(i) Is the student’s claim correct? Give reason.
(ii) Redraw the diagram and mark the direction of magnetic field lines using right-hand thumb rule.

38. A multimedia projector is often used in classrooms and seminar halls to project enlarged images of slides or digital content onto a distant screen. The arrangement generally consists of a powerful light source and a convex lens, which is adjusted to obtain a sharp image on the screen. The clarity of the image depends on the lens–screen distance, as well as the focal length of the convex lens used in the projector. The figure below illustrates how the slide is kept between the focus and the lens to form a magnified real image on the screen.

[Diagram showing a projector setup: Slide at position F, Lens, and magnified Image on a screen.]

A. Which type of lens is used in the projector?
B. What type of image is formed on the screen?
Attempt either subpart C or D.
C. The projector lens has focal length \( f = 10 \text{ cm} \). The sharp image is obtained on a screen \( 200 \text{ cm} \) behind the lens. Find the object (slide) distance \( u \) from the lens.

OR

D. If the slide height is \( 2.0 \text{ cm} \) and the image distance is \( 200 \text{ cm} \) (with the same lens as above), calculate the image height.

39. Attempt either option A or B.

A. A household uses the following electric appliances:
(i) refrigerator of rating 400 W for 10 hours each day.
(ii) two electric fans of rating 80 W each for 6 hours daily.
(iii) six electric tubes of rating 18 W each for 6 hours daily.
Calculate the electricity bill for the household for month of June, if cost of electrical energy is Rs. 3.00 per unit.

OR

B. The values of current \( I \) flowing in a given resistor for the corresponding values of potential difference \( V \) across the resistor are given below:

I (ampere)	0.5	1.0	2.0	3.0	4.0
V (volt)	1.6	3.4	6.7	10.2	13.2

Plot a graph between \( V \) and \( I \) and calculate the resistance of the resistor.