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CBSE Sample Practice Paper — 1 (Session 2026–27)
| Student Name: ______________________ | Roll No.: __________ | Section: __________ |
General Instructions:
1. This question paper is divided into three parts: Part A (Chemistry – 25 marks), Part B (Biology – 30 marks), and Part C (Physics – 25 marks).
2. Each part contains four sections: Section 1 — Very Short Answer (MCQ / Assertion-Reasoning), Section 2 — Short Answer, Section 3 — Long Answer, and Section 4 — Case/Source-based integrated question.
3. Internal choices have been provided in approximately one-third of the questions across the paper; attempt only one option wherever a choice is given.
4. All questions are compulsory unless an internal choice is indicated.
5. Marks for each question are indicated against it.
6. Draw neat, labelled diagrams wherever necessary (diagram-based questions may be answered in words where diagrams cannot be drawn).
7. This is a practice paper prepared in line with the CBSE Class X Science (086) design for the 2026-27 session.
PART A — CHEMISTRY (25 Marks)
Section 1 — Very Short Answer (1 Mark each) — Q1 to Q6
Q1. When dilute hydrochloric acid is added to sodium carbonate, the gas evolved is: 1
Q2. The pH of a neutral solution at room temperature is: 1
Q3. Quicklime reacts vigorously with water to form slaked lime. This reaction is an example of a: 1
Q4. Rusting of iron is fundamentally an example of: 1
Q5. The functional group present in ethanoic acid is: 1
Q6. Assertion (A): Baking soda is commonly used as an ingredient in antacid tablets.
Reason (R): Baking soda is basic in nature and neutralises excess acid present in the stomach. 1
Reason (R): Baking soda is basic in nature and neutralises excess acid present in the stomach. 1
Section 2 — Short Answer (2 Marks each) — Q7 to Q9
Q7. Write a balanced chemical equation for the reaction between zinc granules and dilute sulphuric acid. State the type of reaction involved. 2
Q8. Differentiate between exothermic and endothermic reactions, giving one example of each. 2
Q9. Why does the colour of a copper sulphate solution change when an iron nail is dipped in it? Support your answer with a chemical equation. 2
— OR —
Why should a magnesium ribbon be cleaned with sandpaper before burning it in air? Give one other example of a reaction where surface cleaning is similarly important. 2
Section 3 — Long Answer (3 & 5 Marks) — Q10 to Q11
Q10. What happens when: (a) dilute HCl is added to zinc granules, (b) dilute NaOH solution is added to zinc granules, (c) a few drops of phenolphthalein are added to a solution of NaOH? Write the observations and relevant chemical equations. 3
— OR —
Explain the process of corrosion, taking the rusting of iron as an example. Suggest any three methods by which rusting can be prevented. 3
Q11. (a) Define saponification. Write the chemical equation for the formation of a soap molecule. (2)
(b) Differentiate between soaps and detergents (any two points). (2)
(c) Why do soaps not work effectively in hard water? (1) 5
(b) Differentiate between soaps and detergents (any two points). (2)
(c) Why do soaps not work effectively in hard water? (1) 5
— OR —
(a) Write the chemical formulae of washing soda and baking soda, and give one use of each. (2)
(b) Describe, in brief, how washing soda is manufactured from baking soda. (2)
(c) Why is baking soda used as an antacid? (1) 5
(b) Describe, in brief, how washing soda is manufactured from baking soda. (2)
(c) Why is baking soda used as an antacid? (1) 5
Section 4 — Case-Based Question — Q12
Read the following passage and answer the questions that follow:
Litmus is a natural dye extracted from lichens and is commonly used as an indicator in the laboratory. It turns red in acidic solutions and blue in basic solutions. Since litmus can only indicate whether a substance is acidic, basic, or neutral — but cannot tell us how strong the acid or base is — chemists often use a universal indicator, which is a mixture of several indicators and shows a different colour at different pH values across the full range from strongly acidic to strongly basic.
Litmus is a natural dye extracted from lichens and is commonly used as an indicator in the laboratory. It turns red in acidic solutions and blue in basic solutions. Since litmus can only indicate whether a substance is acidic, basic, or neutral — but cannot tell us how strong the acid or base is — chemists often use a universal indicator, which is a mixture of several indicators and shows a different colour at different pH values across the full range from strongly acidic to strongly basic.
Q12. (i) What colour would a universal indicator show when dipped in a strongly acidic solution? (1)
(ii) Name one olfactory indicator used to test acids and bases. (1)
(iii) A solution turns red litmus paper blue. State the nature of the solution and its approximate pH range. (2)
(iv) Why is litmus alone not sufficient to determine the strength of an acid or a base? (1) 5
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PART B — BIOLOGY (30 Marks)
Section 1 — Very Short Answer (1 Mark each) — Q13 to Q21
Q13. Which organ of the human body produces bile? 1
Q14. Which hormone regulates blood sugar level in the human body? 1
Q15. The male reproductive part of a flower is called the: 1
Q16. Which of the following is a vector-borne disease? 1
Q17. Which part of the human brain is mainly responsible for controlling voluntary actions? 1
Q18. In garden pea plants, which trait is dominant with respect to seed shape? 1
Q19. The junction between two neurons, across which a nerve impulse passes, is called a: 1
Q20. Which of the following is a non-renewable source of energy? 1
Q21. Assertion (A): The sex of a child is determined by the father, not the mother.
Reason (R): All human eggs carry an X chromosome, while sperm may carry either an X or a Y chromosome. 1
Reason (R): All human eggs carry an X chromosome, while sperm may carry either an X or a Y chromosome. 1
Section 2 — Short Answer (2 Marks each) — Q22 to Q25
Q22. Differentiate between a reflex action and a voluntary action, giving one example of each. 2
Q23. What is meant by peristaltic movement? In which part of the human digestive system does it mainly occur? 2
— OR —
Why is the small intestine longer in herbivores than in carnivores? 2
Q24. List any two functions of the hormone testosterone in the human male body. 2
Q25. Traits acquired by an individual during their lifetime are not passed on to their offspring. Give a reason for this statement. 2
Section 3 — Long Answer (3 & 5 Marks) — Q26 to Q27
Q26. Describe the structure of a neuron with reference to any three of its parts and their functions. 3
— OR —
What is double circulation? Explain why it is necessary in the human body. 3
Q27. (a) Explain the process of nutrition in Amoeba. (2)
(b) Differentiate between aerobic and anaerobic respiration. (2)
(c) Name the end products of anaerobic respiration in yeast. (1) 5
(b) Differentiate between aerobic and anaerobic respiration. (2)
(c) Name the end products of anaerobic respiration in yeast. (1) 5
— OR —
(a) Describe the structure of the human excretory system, briefly explaining the function of a nephron. (3)
(b) Why is dialysis needed for a patient suffering from kidney failure? (2) 5
(b) Why is dialysis needed for a patient suffering from kidney failure? (2) 5
Section 4 — Case-Based Question — Q28
Read the following passage and answer the questions that follow:
In any ecosystem, energy flows from producers to various levels of consumers through a food chain. Each step in this chain, called a trophic level, transfers only about 10% of the energy it receives to the next level, most being lost as heat. Because of this steady loss of usable energy, food chains rarely extend beyond three or four trophic levels. In addition to energy loss, certain harmful chemicals that enter the food chain — such as pesticides — do not break down easily and tend to accumulate in increasing concentration at each successive trophic level, a phenomenon known as biological magnification.
In any ecosystem, energy flows from producers to various levels of consumers through a food chain. Each step in this chain, called a trophic level, transfers only about 10% of the energy it receives to the next level, most being lost as heat. Because of this steady loss of usable energy, food chains rarely extend beyond three or four trophic levels. In addition to energy loss, certain harmful chemicals that enter the food chain — such as pesticides — do not break down easily and tend to accumulate in increasing concentration at each successive trophic level, a phenomenon known as biological magnification.
Q28. (i) Define the term 'trophic level'. (1)
(ii) In the food chain grass → deer → lion, identify the primary consumer. (1)
(iii) What is biological magnification? Explain briefly with one example. (2)
(iv) Why is the number of trophic levels in a food chain usually restricted to three or four? (1) 5
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PART C — PHYSICS (25 Marks)
Section 1 — Very Short Answer (1 Mark each) — Q29 to Q34
Q29. The SI unit of electrical resistance is the: 1
Q30. The power of a lens is +2 D. Its focal length and nature are: 1
Q31. When a ray of light passes through a rectangular glass slab, the emergent ray is: 1
Q32. The mirror commonly used as a rear-view/side mirror in vehicles is a: 1
Q33. Which of the following is an excellent conductor of electricity but is not commonly used for making connecting wires because of its high cost? 1
Q34. Assertion (A): Fuse wire used in electrical circuits is made of an alloy having a low melting point and high resistance.
Reason (R): When the current through a circuit exceeds a safe value, the fuse wire melts and breaks the circuit, thereby protecting the appliances. 1
Reason (R): When the current through a circuit exceeds a safe value, the fuse wire melts and breaks the circuit, thereby protecting the appliances. 1
Section 2 — Short Answer (2 Marks each) — Q35 to Q37
Q35. State Ohm's law. Write its mathematical expression, clearly explaining the meaning of each term used. 2
Q36. Two resistors of 4 Ω and 6 Ω are connected in parallel. Calculate their equivalent resistance. 2
— OR —
Two resistors of 4 Ω and 6 Ω are connected in series. Calculate their equivalent resistance. 2
Q37. A person suffering from myopia cannot see distant objects clearly. Name the type of lens used to correct this defect and briefly explain why it works. 2
Section 3 — Long Answer (3 & 5 Marks) — Q38 to Q39
Q38. A concave mirror produces a real, inverted image which is three times the size of the object placed at 10 cm in front of the mirror. Find the position of the image and the focal length of the mirror. 3
— OR —
Explain, giving reasons, why the sky appears blue during the day while the sun appears reddish at sunrise and sunset. 3
Q39. (a) State Joule's law of heating and write its mathematical formula. (2)
(b) Calculate the heat produced in a resistor of 10 Ω when a current of 2 A flows through it for 5 minutes. (2)
(c) State one practical application of the heating effect of electric current. (1) 5
(b) Calculate the heat produced in a resistor of 10 Ω when a current of 2 A flows through it for 5 minutes. (2)
(c) State one practical application of the heating effect of electric current. (1) 5
— OR —
(a) Describe the pattern of magnetic field lines around a straight current-carrying conductor, and state the right-hand thumb rule used to determine their direction. (3)
(b) List any two properties of magnetic field lines. (2) 5
(b) List any two properties of magnetic field lines. (2) 5
Section 4 — Case-Based Question — Q40
Read the following passage and answer the questions that follow:
The human eye can automatically adjust the focal length of its lens to focus objects at different distances on the retina; this ability is called the power of accommodation. When the ciliary muscles cannot bring an object clearly into focus on the retina, a person is said to have a defect of vision. Depending on which point (near or far) is affected, corrective lenses of an appropriate type and power are prescribed by an optometrist to restore normal, comfortable vision.
The human eye can automatically adjust the focal length of its lens to focus objects at different distances on the retina; this ability is called the power of accommodation. When the ciliary muscles cannot bring an object clearly into focus on the retina, a person is said to have a defect of vision. Depending on which point (near or far) is affected, corrective lenses of an appropriate type and power are prescribed by an optometrist to restore normal, comfortable vision.
Q40. (i) Define the power of accommodation of the human eye. (1)
(ii) A person can see nearby objects clearly but cannot see distant objects distinctly. Name this defect of vision. (1)
(iii) Name the type of lens used to correct hypermetropia, and explain briefly why it works. (2)
(iv) Name one more common defect of vision, apart from myopia and hypermetropia. (1) 5
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Design of Question Paper — Blueprint & Analysis
1. Part-wise Marks Distribution
| Part | Subject / Unit | Total Marks |
|---|---|---|
| A | Chemistry — Unit I: Chemical Substances (Nature and Behaviour) | 25 |
| B | Biology — Unit II: World of Living (25) + Unit V: Natural Resources (5) | 30 |
| C | Physics — Unit III: Natural Phenomena (12) + Unit IV: Effects of Current (13) | 25 |
| Total | 80 | |
2. Section-wise Typology (per Part)
| Section | Question Type | Chemistry | Biology | Physics |
|---|---|---|---|---|
| 1 | VSA (MCQ incl. 1 Assertion–Reason) | 6 × 1 = 6 | 9 × 1 = 9 | 6 × 1 = 6 |
| 2 | Short Answer (2 marks) | 3 × 2 = 6 | 4 × 2 = 8 | 3 × 2 = 6 |
| 3 | Long Answer (3 + 5 marks) | 3 + 5 = 8 | 3 + 5 = 8 | 3 + 5 = 8 |
| 4 | Case-Based (5 marks) | 5 | 5 | 5 |
| Part Total | 25 | 30 | 25 | |
3. Competency-Level Distribution
| Competency Level | Description | Approx. Marks | Percentage |
|---|---|---|---|
| Knowledge & Understanding | State, define, list, describe, identify | 40 | 50% |
| Application of Knowledge | Calculate, illustrate, show, explain, distinguish | 24 | 30% |
| Analyse, Evaluate & Create | Interpret, analyse, compare, contrast, examine | 16 | 20% |
| Total | 80 | 100% |
4. Internal Choice Summary
Internal choices are provided in Q9, Q11, Q23, Q26, Q27, Q36, Q38 and Q39 — approximately one-third of the total questions across the paper, in line with the CBSE 2026-27 design.
5. Topics Excluded (as per current 2026-27 exclusions)
• Periodic Classification of Elements (Unit I)
• Evolution — speciation, fossils, evidence of evolution (only Heredity/Mendelian genetics is retained from this chapter)
• Electric Motor, Electromagnetic Induction, and Electric Generator (Unit IV)
• Content found only in "Do You Know?" / additional-information boxes of the NCERT textbook
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Answer Key
Part A — Chemistry
Q1. (B) Carbon dioxide Q2. (B) 7 Q3. (A) Combination reaction Q4. (A) Oxidation Q5. (C) –COOH Q6. (A)
Q7. Zn + H₂SO₄ → ZnSO₄ + H₂↑; this is a displacement reaction.
Q8. Exothermic reactions release heat (e.g., burning of natural gas); endothermic reactions absorb heat (e.g., decomposition of calcium carbonate on heating).
Q9. The blue colour fades because iron displaces copper from copper sulphate solution: Fe + CuSO₄ → FeSO₄ + Cu. OR: Magnesium reacts with atmospheric oxygen/moisture to form a layer of MgO on its surface, which must be removed for a clean reaction; a similar example is the tarnishing of aluminium surfaces by an oxide layer.
Q10. (a) Zn + 2HCl → ZnCl₂ + H₂↑ (effervescence, gas is combustible); (b) Zn + 2NaOH → Na₂ZnO₂ + H₂↑ (zinc shows amphoteric behaviour); (c) solution turns pink, confirming NaOH is basic. OR: Corrosion of iron (rusting) is the gradual formation of hydrated iron(III) oxide (Fe₂O₃·xH₂O) on the surface in presence of air and moisture; prevention methods include painting, galvanising, and applying oil/grease.
Q11. (a) Saponification is the reaction of a fat/oil with an alkali to form soap and glycerol. (b) Soaps are less effective in hard water and form scum, whereas detergents work well even in hard water; soaps are biodegradable, detergents may not always be. (c) Hard water contains Ca²⁺/Mg²⁺ ions which react with soap to form an insoluble scum, reducing its cleaning action. OR: Washing soda: Na₂CO₃·10H₂O, used in glass/soap manufacture; baking soda: NaHCO₃, used in cooking/antacids. Washing soda is obtained by heating baking soda. Baking soda neutralises excess stomach acid because it is mildly basic.
Q12. (i) Red. (ii) Onion or vanilla extract (any olfactory indicator). (iii) The solution is basic; approximate pH range 8–14. (iv) Litmus only shows colour change (acidic/basic/neutral) but does not indicate the concentration or strength of the acid/base — a universal indicator or pH scale is needed for that.
Part B — Biology
Q13. (B) Liver Q14. (C) Insulin Q15. (B) Stamen Q16. (A) Malaria Q17. (C) Cerebrum Q18. (A) Round Q19. (A) Synapse Q20. (A) Coal Q21. (A)
Q22. Reflex action is a rapid, automatic, involuntary response controlled by the spinal cord (e.g., withdrawing hand from a hot object); voluntary action is a consciously controlled response involving the brain (e.g., writing).
Q23. Peristaltic movement refers to the rhythmic wave-like muscular contractions that push food forward; it occurs throughout the alimentary canal, especially the oesophagus and small intestine. OR: The small intestine is longer in herbivores because cellulose digestion requires more time and surface area for microbial breakdown.
Q24. Testosterone brings about changes in appearance at puberty (facial hair, deepening of voice) and is responsible for the formation of sperm.
Q25. Acquired traits affect only somatic (body) cells, not germ cells (sperm/egg), so they cannot be passed on through DNA to offspring.
Q26. Any three parts: dendrite (receives impulse), cell body/cyton (contains nucleus, maintains cell), axon (conducts impulse away), synapse (transmits impulse to next neuron). OR: Double circulation is the passage of blood twice through the heart in one complete cycle (pulmonary + systemic); it is necessary to keep oxygenated and deoxygenated blood separate, ensuring efficient oxygen supply for a high-energy-demand body.
Q27. (a) Amoeba engulfs food using pseudopodia (phagocytosis), forms a food vacuole where digestion occurs, and undigested matter is expelled. (b) Aerobic respiration uses oxygen and releases more energy (glucose → CO₂ + H₂O); anaerobic respiration occurs without oxygen and releases less energy. (c) Ethanol and carbon dioxide. OR: The excretory system consists of kidneys, ureters, urinary bladder and urethra; the nephron is the structural and functional unit of the kidney, filtering blood and forming urine through filtration, reabsorption and secretion. (b) Dialysis artificially removes nitrogenous waste from blood when kidneys fail to do so, preventing toxic build-up.
Q28. (i) A trophic level is each step in a food chain at which transfer of energy takes place. (ii) Deer. (iii) Biological magnification is the increasing concentration of harmful, non-biodegradable substances (e.g., pesticides like DDT) at each successive trophic level of a food chain. (iv) Because only about 10% of energy is transferred to the next level, and most is lost as heat, so very little usable energy remains beyond 3-4 levels.
Part C — Physics
Q29. (B) Ohm Q30. (B) 50 cm, convex Q31. (B) Parallel to the incident ray Q32. (B) Convex mirror Q33. (C) Silver Q34. (A)
Q35. Ohm's law states that the current through a conductor is directly proportional to the potential difference across it, provided temperature remains constant: V = IR, where V is potential difference (volt), I is current (ampere), R is resistance (ohm).
Q36. Parallel: 1/R = 1/4 + 1/6 = 5/12 ⇒ R = 2.4 Ω. OR: Series: R = 4 + 6 = 10 Ω.
Q37. A concave (diverging) lens is used, as it diverges the incoming light rays, moving the image formed in front of the retina back onto the retina for a myopic eye.
Q38. Using magnification m = −3 (real, inverted, magnified): m = −v/u ⇒ −3 = −v/(−10) ⇒ v = −30 cm. Using mirror formula 1/v + 1/u = 1/f: 1/(−30) + 1/(−10) = 1/f ⇒ f = −7.5 cm (concave mirror). OR: The sky appears blue because shorter (blue) wavelengths of sunlight are scattered much more by atmospheric particles than longer wavelengths (Rayleigh scattering); at sunrise/sunset, sunlight travels a longer path through the atmosphere, so most blue light is scattered away, leaving mainly red/orange light to reach our eyes.
Q39. (a) Joule's law of heating: H = I²Rt, where H is heat produced, I is current, R is resistance, t is time. (b) H = (2)² × 10 × 300 = 12,000 J = 12 kJ. (c) Electric heater / electric iron / fuse (any one). OR: (a) Magnetic field lines around a straight current-carrying conductor are concentric circles around the wire; direction found using the right-hand thumb rule (thumb points in current direction, curled fingers show field direction). (b) Field lines never intersect; they are closer together where the field is stronger.
Q40. (i) The power of accommodation is the ability of the eye lens to adjust its focal length to focus objects at varying distances clearly on the retina. (ii) Myopia (short-sightedness). (iii) Convex lens; it converges the light rays so that the image, which would otherwise form behind the retina, is brought forward onto the retina. (iv) Presbyopia (or astigmatism).
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Detailed Marking Scheme
General Marking Guidelines
• Section 1 (MCQ/Assertion-Reason): 1 mark for the correct option only; no partial credit.
• Section 2 (2-mark questions): marks are typically split as 1 mark for the correct concept/definition/equation and 1 mark for correct explanation, example, or calculation.
• Section 3 (3 & 5-mark questions): marks awarded step-wise — correct concept/law/definition, correct working/equation, and correct final answer/conclusion with reasoning. Alternative correct methods (e.g., different but valid worked solutions) must be given full credit.
• Section 4 (Case-based, 5 marks): each sub-part carries independent marks as indicated (1, 1, 2, 1); an error in one sub-part should not affect marks for the others.
• Numerical questions: full credit only if correct formula, correct substitution, correct final answer with unit are all present; partial credit for correct formula/substitution even if the final numeric answer has a minor computational error.
• Chemical equations: 1 mark is generally allotted for correctly balanced equations; unbalanced but otherwise correct equations may be awarded partial credit as per the specific scheme used by the evaluator.
Part-wise Mark Allocation Recap
| Part | Section 1 | Section 2 | Section 3 | Section 4 | Total |
|---|---|---|---|---|---|
| A — Chemistry | 6 | 6 | 8 | 5 | 25 |
| B — Biology | 9 | 8 | 8 | 5 | 30 |
| C — Physics | 6 | 6 | 8 | 5 | 25 |
| Grand Total | 21 | 20 | 24 | 15 | 80 |
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