SCIENCE - Code no. 086
Sample Question Paper

Class X (2025-26)

• This question paper consists of 39 questions in 3 sections. Section A is Biology, Section B is Chemistry, and Section C is Physics.
• All questions are compulsory. However, an internal choice is provided in some questions. A student is expected to attempt only one of these questions.
• Max. Marks: 80  |  Time Allowed: 3 hours

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Section A: Biology

1. Select the group in which all organisms have the same mode of nutrition.
   A. Cuscuta, yeast, legumes, leeches and tapeworm
   B. Cactus, ticks, lice, leeches and cow
   C. Cuscuta, ticks, lice, leeches and tapeworm
   D. Cactus, grass, lice, lion and tapeworm
2. Which of the following indicates the products formed after breakdown of glucose in our muscle cells when there is lack of oxygen?
   A. Ethanol + carbon dioxide + Energy
   B. Lactic acid + Energy
   C. Lactic acid + carbon monoxide + Energy
   D. Carbon dioxide + Water + Energy
3. Which of the following is a correct combination of function and part of the brain?
   A. Posture and balance: Cerebrum
   B. Salivation: Medulla in midbrain
   C. Hunger: Pons in hindbrain
   D. Blood pressure: Medulla in hindbrain
4. The blood glucose level in a patient was very high. It may be due to inadequate secretion of:
   A. growth hormone from pituitary gland
   B. oestrogen from ovary
   C. insulin from pituitary gland
   D. insulin from pancreas
5. In a cross between black furred rabbit (B) and white furred rabbit (b), all offspring were found to have black fur. What can be inferred about the genetic makeup of the parent rabbits?
   A. BB × bb
   B. Bb × Bb
   C. Bb × bb
   D. bb × bb
6. Which are the correct statements related to ozone?
   (i) Ozone layer helps in increasing the UV radiations reaching earth.
   (ii) Ozone is a deadly poison.
   (iii) Ozone layer shields the earth from UV radiations.
   (iv) Ozone layer prevents UV rays which cause skin cancer.
   (v) Ozone is formed with the help of Chlorofluorocarbons.
   A. (i), (ii), (iii)
   B. (ii), (iii), (iv)
   C. (iii), (iv), (v)
   D. (i), (iv), (v)
7. Which of the following human activities has resulted in an increase of non-biodegradable substances?
   A. Organic farming
   B. Increase in tree plantation
   C. Use of plastic as packaging material
   D. Composting of kitchen waste
8. Assertion (A): Tallness of a pea plant is controlled by an enzyme.
   Reason (R): The gene for that enzyme makes proteins which help the plant to be tall.
   Options:
   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): Vulture will always have the least amount of pesticides in a food chain.
   Reason (R): Vulture occupies the last trophic level and it gets only 10% of energy of the previous trophic level.
   Options: (same as above)
10. Unlike animals, plants do not have any excretory products as they do not eat food. Comment upon the statement with justification.
11. Attempt either option A or B.
    Option A: How many chambers are there in the heart of the following organisms? How is mixing of oxygenated and deoxygenated blood prevented?
    (i) Fishes (ii) Humans
    OR Option B: Explain the mechanism by which water is transported in plants?
12. About 100 acres of forest land was declared as Natural Reserve Park. The organisms present included: rabbit, frog, grass, fish, fox, water insects, zebra, peacock, snake, trees, bird, owl, insects, tiger, vulture, duck. Create a food web with two separate food chains and different producers.
13. Draw and explain how nerve cells help in transmission of impulses?
14. In a genetic experiment, plants with pure round green seeds (RRyy) were crossed with wrinkled yellow seeds (rrYY).
    (i) Show the gametes formed when F1 was self-pollinated.
    (ii) Out of 144 seeds produced, show the trait ratio inherited among the saplings.
15. Neha consumed boiled sweet potatoes and boiled eggs for breakfast. Steps in digestion:
    
    A. Which is rich in proteins, where does digestion start, name enzymes, conditions, and glands.
    OR
    B. Which contains fats? How is it digested?
    C. Which item is rich in starch, how is its digestion initiated?
    D. In the human alimentary canal diagram (labeled L, M, N, O, P), which part will have the most digested food after digestion is complete?
    (For visually impaired students: How does the alimentary canal take up digested food?)
16. Attempt either option A or B.
    Option A: Puneet wanted to grow banana plants.
    (i) Should he use seeds or an alternative? Justify.
    (ii) Variations in banana offspring—what causes them, and are they good or bad?
    OR Option B: Annie does research on the number of fruits in watermelons with/without pollinators in glass houses A and B.
    (i) Compare results, reason.
    (ii) Three changes after fertilization in a flower.

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Section B: Chemistry

17. Which equations represent redox reactions and the values for 'p' and 'q'?
    Equation 1: Fe₂O₃ + 2Al → Al₂O₃ + pFe + heat
    Equation 2: 2C₄H₁₀ + 13O₂ → 8CO₂ + qH₂O
    A. Only equation 1; p=1, q=3
    B. Both equations; p=2, q=4
    C. Only equation 2; p=2, q=10
    D. Both equations; p=2, q=10
18. Which statements about oxide reactions with acid/base are correct?
    I. Aluminium oxide reacts with both dilute HCl and NaOH.
    II. Calcium oxide reacts with both.
    III. Zinc oxide reacts with both.
    IV. Sulphur dioxide reacts with neither.
    A. I and II
    B. I and III
    C. II and IV
    D. III and IV
19. Iron nail tests in copper(II) sulphate and silver nitrate. Which is correct? (Options describe color changes/reactions.)
20. Methyl orange in HCl and NaOH colors.
    (Table format, options for observed colors.)
21. Which dissolved substance gives the highest pH?
    A. Sulphuric acid
    B. Acetic acid
    C. Magnesium hydroxide
    D. Sodium hydroxide
22. Why does milkiness disappear when excess CO₂ is passed through lime water? (Options regarding conversions of calcium carbonate/bicarbonate.)
23. Precipitate in the barium chloride and sodium sulphate reaction.
    A. BaCl₂
    B. BaSO₄
    C. Na₂SO₄
    D. NaCl
24. Assertion-Reason about homologous series and unsaturated hydrocarbons. (Options detail true/false/explanation relationships.)
25. Lab activity: aluminium wire, heating, observing pin falls, questions about replacing with silver, melting, justification.
26. Attempt either option A or B.
    Option A: Element 'X' stored in kerosene, forms ionic chloride, method of extraction, and reactions.
    OR Option B: Copper domes appear greenish—why, should they be replaced with iron, why was copper used?
27. Electrolysis of distilled water (with diagrams). Questions about expected gases, bulb not glowing, substance added.
    (Alternate: Visually impaired—types of reaction.)
28. Phenolphthalein titration: adding H₂SO₄ to NaOH, table of results. Further calculations, questions about concentrated acid, calculation of mL of NaOH, observation with swaps, balanced equation, type of reaction.
29. Attempt either option A or B.
    Option A: Hydrocarbon C_xH_y combustion equation, values of x/y, IUPAC name, electron-dot structure, corresponding alcohol, hydrogenation.
    OR Option B: Atoms P and Q electronic structure—bonding, formula, solution acidity, reaction with ethanol, bonding with carbon.
    (Alternate: Compare oxide bonding, conductor in molten state, state of CaO and CO₂, valency in CO₂.)

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Section C: Physics

30. Reflection from curved surfaces; identify correct statements about concave, convex mirrors, image formula.
31. Why do we see the sky as blue? (Options explaining light scattering etc.)
32. Assertion-Reason about image position and mirror formula (convex mirror and focal length).
33. Optical instrument (diagram): identify, image type, focal length calculation.
    (Alternate for visually impaired: virtual image with convex lens, focus and sunlight, paper burning.)
34. Attempt either option A or B.
    Option A: Given circuit with resistors, questions on effective resistance, current.
    OR Option B: Circuit with resistors and ammeters; current in resistor, ammeter readings.
    (Alternate for visually impaired: four resistors, max/min resistance; calculating resistance for wire.)
35. Image of corrective lens use for vision defect: identify defect, type of lens for correction, draw ray diagram.
    (Alternate: dispersion of light, conditions for dispersion, presbyopia.)
36. Student needs to make a 0.12Ω resistor; given copper wire diameter/length, resistivity. Calculate cross-sectional area, required length.
37. Magnetic field lines diagram; claim about field strength at positions, redraw with field direction.
38. DSLR Camera diagram, lens and sensor diagram:
    A. Type of lens used in camera.
    B. Type of image formed.
    C. Using lens formula, calculate object distance (data given for close-up).
    D. For image height and object distance, find lens focal length.
    (Alternate for visually impaired: lens usage in flashlight/solar cooker, object-image distances, lens focal length calculations.)
39. Attempt either option A or B.
    Option A: Resistor arrangement circuit: calculate current, voltmeter readings, given power in resistor.
    OR Option B: Circuit with heating elements and switches; resistance calculation, current with certain switches, power dissipated.
    (Alternate for visually impaired: household fuse/appliance arrangement, total current/power/fuse suitability, heat generation in resistors.)

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