JKBOSE Class 10th Science Question Paper 2026 with answers key

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JKBOSE Class 10th Science – Full Sample Question Paper (2025–26)

Jammu & Kashmir Board of School Education
Secondary School Examination (Class 10th)
Subject: Science
Session: 2025 – 2026

Time Allowed: 3 Hours
Maximum Marks: 80

General Instructions:

  1. All questions are compulsory.
  2. This question paper consists of 40 questions divided into four sections – A, B, C and D.
  3. Section A contains 18 very short answer questions of 1 mark each.
  4. Section B contains 8 short answer questions of 2 marks each.
  5. Section C contains 7 short answer questions of 3 marks each.
  6. Section D contains 7 long answer questions of 5 marks each.
  7. Draw neat and labelled diagrams wherever necessary.
  8. Write the answers in legible handwriting.

SECTION – A (1 × 18 = 18 marks)

Q1. When a fine beam of sunlight enters a smoke-filled room through a small hole, the path of the light beam becomes visible. It is caused due to:
(a) Atmospheric refraction
(b) Dispersion of light
(c) Refraction of light
(d) Tyndall effect

Q2. Which of the following has a relatively greater Refractive Index?
(a) Rock salt
(b) Diamond
(c) Air
(d) Ice

Q3. A student obtains a blurred image of a distant object on a screen using a convex lens. To obtain a distinct image on the screen, he should move the lens:
(a) Towards the screen
(b) Away from the screen
(c) Either away or towards the screen
(d) To a position very far away from the screen

Q4. The human eye forms the image of an object at its:
(a) Cornea
(b) Iris
(c) Pupil
(d) Retina

Q5. Which of the following is a primary consumer in a grassland ecosystem?
(a) Grasshopper
(b) Frog
(c) Snake
(d) Hawk

Q6. Why does a ray of light bend when it travels from one medium to another?

Q7. State the role of the pancreas in the digestion of food.

Q8. Write the chemical name and formula of washing soda.

Q9. What is meant by a redox reaction?

Q10. Name the hormone secreted by the thyroid gland and state its function.

Q11. Define the term ‘Reflex action’.

Q12. Why is it necessary to conserve water resources?

Q13. What is the SI unit of electric current?

Q14. State one difference between a food chain and a food web.

Q15. Name the gas evolved when dilute hydrochloric acid reacts with zinc granules.

Q16. Why do we see the sun reddish at the time of sunrise and sunset?

Q17. What is the full form of DNA?

Q18. Mention the pH range of human blood.

SECTION – B (2 × 8 = 16 marks)

Q19. State two differences between a convex lens and a concave lens.

Q20. What is meant by ‘corrosion’? Give one example of corrosion.

Q21. Explain the process of photosynthesis. Write the overall chemical equation for the process.

Q22. What is the role of the ozone layer in the atmosphere? How is it getting depleted?

Q23. Write the balanced chemical equation for the reaction between sodium carbonate and hydrochloric acid. Mention the physical states of all reactants and products.

Q24. State the laws of reflection of light.

Q25. Differentiate between biodegradable and non-biodegradable wastes with suitable examples.

Q26. Explain the term ‘Magnetic field lines’.

SECTION – C (3 × 7 = 21 marks)

Q27. What is meant by ‘acid rain’? Write any two harmful effects of acid rain.

Q28. Explain the process of digestion in human beings. Name the organs involved and their functions.

Q29. State Ohm’s law. Draw a labelled circuit diagram to verify Ohm’s law.

Q30. (a) What is a homologous series? Write the general formula of alkanes.
(b) Draw the structural formula of ethane and ethene.

Q31. Explain the formation of a rainbow with the help of a diagram.

Q32. What is meant by ‘sustainable management’? State any two ways to conserve natural resources.

Q33. Describe the structure and function of a nephron in the human excretory system.

SECTION – D (5 × 5 = 25 marks)

Q34. (a) State the laws of reflection of light.
(b) An object is placed 20 cm in front of a concave mirror of focal length 15 cm. Find the position and nature of the image.

Q35. (a) Explain the process of nutrition in Amoeba with the help of diagrams.
(b) What is the role of hydrochloric acid in the stomach?

Q36. (a) What is an electric circuit?
(b) State the difference between a series and a parallel circuit.
(c) Calculate the equivalent resistance of two resistors of 5 Ω and 10 Ω connected in parallel.

Q37. (a) What are the different types of chemical reactions? Explain with one example each.
(b) Balance the following chemical equation: Fe + H₂O → Fe₃O₄ + H₂

Q38. Explain the structure of the human eye with the help of a neat and labelled diagram. State the function of the iris and the pupil.

Q39. (a) What is meant by ‘Regeneration’ and ‘Fragmentation’ in organisms?
(b) Explain the process of reproduction in Hydra.

Q40. (a) What is the role of decomposers in an ecosystem?
(b) Explain the flow of energy in a food chain with the help of a diagram.
(c) Why is the flow of energy unidirectional?

ANSWER KEY

SECTION – A

  1. (d) Tyndall effect — The scattering of light by colloidal particles in smoke makes the light path visible.
  2. (b) Diamond — It has a refractive index of about 2.42, the highest among the given options.
  3. (a) Towards the screen — For a distant object, the image forms at the focal point. Moving the lens towards the screen brings the image into focus.
  4. (d) Retina — The retina is the light-sensitive screen at the back of the eye where the image is formed.
  5. (a) Grasshopper — It feeds directly on grass (producers), making it a primary consumer.
  6. A ray of light bends because its speed changes when it passes from one medium to another. This phenomenon is called refraction.
  7. The pancreas secretes pancreatic juice containing digestive enzymes — trypsin (digests proteins), amylase (digests carbohydrates), and lipase (digests fats).
  8. Chemical name: Sodium carbonate decahydrate. Formula: Na₂CO₃·10H₂O.
  9. A redox reaction is one in which oxidation and reduction occur simultaneously.
  10. Hormone: Thyroxine. Function: Regulates carbohydrate, protein, and fat metabolism in the body.
  11. A reflex action is a sudden, involuntary response of the body to a stimulus, controlled by the spinal cord without conscious thought.
  12. Water is a finite resource essential for life. Conserving it ensures availability for future generations and maintains ecological balance.
  13. Ampere (A).
  14. A food chain follows a single linear path of energy transfer, while a food web consists of multiple interconnected food chains.
  15. Hydrogen gas (H₂).
  16. During sunrise and sunset, sunlight travels a longer distance through the atmosphere. Shorter wavelengths (blue, green) are scattered away, and mostly red light reaches our eyes.
  17. Deoxyribonucleic Acid.
  18. The pH of human blood ranges from 7.35 to 7.45 (slightly basic).

SECTION – B

  1. (i) A convex lens is thicker in the middle and converges light; a concave lens is thinner in the middle and diverges light.
    (ii) A convex lens can form both real and virtual images; a concave lens always forms virtual, erect, and diminished images.
  2. Corrosion is the gradual destruction of a metal due to chemical reactions with its environment. Example: Rusting of iron (formation of iron oxide on exposure to moist air).
  3. Photosynthesis is the process by which green plants synthesize food (glucose) from carbon dioxide and water using sunlight and chlorophyll, releasing oxygen.
    Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in the presence of sunlight and chlorophyll).
  4. The ozone layer absorbs harmful ultraviolet (UV) radiations from the Sun, protecting living organisms. It is depleted mainly by chlorofluorocarbons (CFCs) used in refrigerators and air conditioners.
  5. Na₂CO₃(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) + CO₂(g)
    Sodium carbonate (solid) reacts with hydrochloric acid (aqueous) to form sodium chloride (aqueous), water (liquid), and carbon dioxide (gas).
  6. (i) The angle of incidence is equal to the angle of reflection.
    (ii) The incident ray, the reflected ray, and the normal to the surface at the point of incidence all lie in the same plane.
  7. Biodegradable wastes can be decomposed by microorganisms (e.g., vegetable peels, paper). Non-biodegradable wastes cannot be decomposed by microorganisms (e.g., plastic, glass).
  8. Magnetic field lines are imaginary curves along which a hypothetical free north pole would move. They show the direction and strength of the magnetic field around a magnet.

SECTION – C

  1. Acid rain is rain with a pH lower than 5.6, caused by the dissolution of acidic gases like sulphur dioxide and nitrogen oxides in rainwater.
    Harmful effects: (i) It corrodes buildings and monuments. (ii) It damages crops and harms aquatic life by acidifying water bodies.
  2. Digestion is the breakdown of complex food into simpler absorbable forms.
    Organs involved:
  • Mouth — Salivary amylase digests starch.
  • Stomach — HCl kills bacteria; pepsin digests proteins.
  • Small intestine — Bile emulsifies fats; pancreatic and intestinal enzymes complete digestion; nutrients are absorbed through villi.
  • Large intestine — Absorbs water and forms faeces.
  1. Ohm’s law: The current flowing through a conductor is directly proportional to the potential difference across its ends, provided temperature remains constant (V = IR).
    Circuit diagram: A battery, key, rheostat, ammeter (connected in series), voltmeter (connected in parallel across the resistor), and a resistor are arranged to verify Ohm’s law.
  2. (a) A homologous series is a family of organic compounds having the same functional group and similar chemical properties, with successive members differing by a –CH₂– unit. General formula of alkanes: CₙH₂ₙ₊₂.
    (b) Ethane: CH₃–CH₃ (single bond between two carbon atoms).
    Ethene: CH₂=CH₂ (double bond between two carbon atoms).
  3. A rainbow is formed due to dispersion, refraction, and internal reflection of sunlight by water droplets in the atmosphere. When sunlight enters a raindrop, it is refracted, dispersed into seven colours, internally reflected, and refracted again as it emerges, forming a band of colours in the sky.
  4. Sustainable management means using natural resources wisely so that they are available for future generations.
    Ways to conserve: (i) Reforestation and afforestation. (ii) Rainwater harvesting and reducing water pollution.
  5. A nephron is the functional unit of the kidney. It consists of a Bowman’s capsule (containing the glomerulus) and a long tubule (proximal tubule, loop of Henle, distal tubule). Blood is filtered in the glomerulus, useful substances (glucose, water, salts) are reabsorbed in the tubule, and urine is formed.

SECTION – D

  1. (a) Laws of reflection: (i) Angle of incidence = angle of reflection. (ii) Incident ray, reflected ray, and normal lie in the same plane.
    (b) Given: u = –20 cm, f = –15 cm.
    Using mirror formula: 1/v + 1/u = 1/f
    1/v – 1/20 = –1/15 → 1/v = –1/15 + 1/20 = (–4 + 3)/60 = –1/60
    v = –60 cm.
    The image is formed 60 cm in front of the mirror. It is real, inverted, and magnified.
  2. (a) Amoeba feeds using pseudopodia (false feet). It surrounds the food particle and engulfs it, forming a food vacuole where digestion occurs.
    (b) Hydrochloric acid in the stomach kills bacteria and provides an acidic medium for pepsin to digest proteins.
  3. (a) An electric circuit is a closed path through which electric current flows.
    (b) In a series circuit, there is one path and the same current flows through all components. In a parallel circuit, there are multiple paths and the voltage across each component is the same.
    (c) 1/R = 1/5 + 1/10 = 2/10 + 1/10 = 3/10. Therefore, R = 10/3 Ω ≈ 3.33 Ω.
  4. (a) Types of chemical reactions: Combination (A + B → AB), Decomposition (AB → A + B), Displacement (A + BC → AC + B), Double displacement (AB + CD → AD + CB), with one example each.
    (b) Balanced equation: 3Fe + 4H₂O → Fe₃O₄ + 4H₂
  5. The human eye consists of the cornea (outer transparent covering), iris (coloured diaphragm), pupil (opening in the iris), lens (focuses light), and retina (light-sensitive screen). The optic nerve carries signals to the brain.
    Iris function: Controls the size of the pupil.
    Pupil function: Regulates the amount of light entering the eye.
  6. (a) Regeneration is the ability of an organism to regrow lost body parts (e.g., Planaria). Fragmentation is the breaking of the parent body into pieces, each developing into a new individual (e.g., Spirogyra).
    (b) Hydra reproduces by budding. A small bulge (bud) develops on the parent’s body, grows, and eventually detaches to form a new Hydra.
  7. (a) Decomposers break down dead organic matter and recycle nutrients back into the ecosystem.
    (b) Energy flows from producers (plants) to primary consumers (herbivores) to secondary consumers (carnivores) and decomposers. At each level, about 90% of energy is lost as heat (10% law).
    (c) Energy flow is unidirectional because energy is lost as heat at each trophic level and cannot be reused by the previous level.

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