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Class 10 Science: questions from CBSE board papers, by chapter
Every question of the 4 CBSE board exam papers Shishya has solved (2026 Q.P. 31/1/1, 2025 Q.P. 31/1/1, 2024 Q.P. 31/1/1, 2023 Q.P. 31/1/1), listed under the NCERT chapter it was asked from. The question lines are in Shishya's own shorter words; each links to its step-by-step solution, and the paper page links CBSE's own question paper. Marks per chapter count every listed question, including both sides of an either/or choice.
Chemical Reactions and Equations
16 questions, 22 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q17 · 1 markClassify both: (i) AgNO₃ + NaCl → NaNO₃ + AgCl and (ii) K₂SO₄ + BaCl₂ → BaSO₄ + 2KCl.
- Asked in CBSE 2026 · 31/1/1 · Q19 · 1 markWhich gases come off when lead(II) nitrate is heated?
- Asked in CBSE 2026 · 31/1/1 · Q26(a) · 1 markIn ZnO + C → Zn + CO, name what is oxidised and what is reduced.
- Asked in CBSE 2026 · 31/1/1 · Q26(b) · 1 markBalance Pb(NO₃)₂ + KI → PbI₂ + KNO₃.
- Asked in CBSE 2026 · 31/1/1 · Q26(c) · 1 markGive one example each of decomposition by electricity and by sunlight.
- Asked in CBSE 2025 · 31/1/1 · Q1 · 1 markWhen water is electrolysed, what is the mass ratio of hydrogen to oxygen gas set free (MH : MO)?
- Asked in CBSE 2025 · 31/1/1 · Q17 · 1 markAssertion: most decomposition reactions absorb heat. Reason: the breakdown of organic matter into compost gives out heat.
- Asked in CBSE 2025 · 31/1/1 · Q21 · 2 marksZinc granules are put in dilute sulphuric acid in a corked conical flask. Give two observations showing a chemical change has happened.
- Asked in CBSE 2024 · 31/1/1 · Q2 · 1 markWhich decomposition uses light as its energy source: FeSO₄ heating, electrolysis of water, AgBr breakdown, or CaCO₃ heating?
- Asked in CBSE 2024 · 31/1/1 · Q7 · 1 markWhy is MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂ a redox reaction?
- Asked in CBSE 2024 · 31/1/1 · Q21 · 2 marksWhat kind of reaction occurs between calcium oxide and water? Support it with the balanced equation.
- Asked in CBSE 2024 · 31/1/1 · Q27 · 3 marksGive one equation each for a reaction showing (i) colour change, (ii) temperature change, (iii) a precipitate; state the colour change, rise/fall of temperature, or the precipitate.
- Asked in CBSE 2023 · 31/1/1 · Q2 · 1 markLead nitrate is heated in a test tube over a burner and brown fumes come out. What causes the brown fumes?
- Asked in CBSE 2023 · 31/1/1 · Q3 · 1 markBalance MnO₂ + x HCl → MnCl₂ + y H₂O + z Cl₂. Find x, y, z.
- Asked in CBSE 2023 · 31/1/1 · Q17 · 1 markA: Blue copper sulphate solution loses its colour when lead is put in it. R: Lead is more reactive than copper and displaces it from its salt.
- Asked in CBSE 2023 · 31/1/1 · Q27 · 3 marks(a) Name the reducing agent in: (i) 4NH₃ + 5O₂ → 4NO + 6H₂O, (ii) H₂O + F₂ → HF + HOF, (iii) Fe₂O₃ + 3CO → 2Fe + 3CO₂, (iv) 2H₂ + O₂ → 2H₂O. (b) Define redox reaction in terms of oxygen gain/loss.
Acids, Bases and Salts
19 questions, 31 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q18 · 1 markWhich indicator could a blind student use to test acids and bases?
- Asked in CBSE 2026 · 31/1/1 · Q22 · 1 markName natural sources of oxalic acid, lactic acid and methanoic acid, in that order.
- Asked in CBSE 2026 · 31/1/1 · Q27(a) · 3 marksExplain the chlor-alkali process with its equation and name the products at the anode and the cathode.
- Asked in CBSE 2026 · 31/1/1 · Q27(b) · 3 marksGive the preparation, with balanced equations, of (i) baking soda, (ii) bleaching powder, (iii) plaster of Paris.
- Asked in CBSE 2025 · 31/1/1 · Q3 · 1 markOn a pH scale, solution A is at pH 5, B at pH 7, C at pH 13 and D at pH 3. Classify A, B, C and D in that order.
- Asked in CBSE 2025 · 31/1/1 · Q4 · 1 markWhat is common to these three reactions: dilute HCl with NaOH; MgO with dilute HCl; CO₂ with NaOH?
- Asked in CBSE 2025 · 31/1/1 · Q37(a) · 1 markCase: common salt from seawater and rock salt is a raw material for many chemicals. Write the balanced equation for electrolysis of brine.
- Asked in CBSE 2025 · 31/1/1 · Q37(b) · 1 markGive two uses of any one product of brine electrolysis.
- Asked in CBSE 2025 · 31/1/1 · Q37(c)(i) · 2 marksSalt A is a mild, non-corrosive base used to make cooking faster; heating it strongly gives compound B, which is used to soften permanently hard water. Name A and B and write the equation for heating A.
- Asked in CBSE 2025 · 31/1/1 · Q37(c)(ii) · 2 marksWhat is water of crystallisation? Name two salts that contain it.
- Asked in CBSE 2024 · 31/1/1 · Q1 · 1 markGranulated zinc is warmed with about 2 mL of NaOH solution. Which balanced equation describes the reaction?
- Asked in CBSE 2024 · 31/1/1 · Q5 · 1 markAmong FeSO₄, CuSO₄, CaSO₄ and Na₂CO₃, which crystal holds the most water of crystallisation per formula unit?
- Asked in CBSE 2024 · 31/1/1 · Q28 · 3 marks(i) Tomato juice has pH 4.6; how will it taste and why? (ii) Tell a strong acid from a weak base by the ions they form in water. (iii) How does acid rain harm aquatic animals?
- Asked in CBSE 2023 · 31/1/1 · Q1 · 1 markDilute HCl reacts with sodium carbonate and the gas is bubbled through solution X (aqueous calcium hydroxide). X first turns milky, then colourless. Which explanation is right?
- Asked in CBSE 2023 · 31/1/1 · Q4 · 1 markA table gives solution, pH-paper colour, approximate pH and nature for lemon juice, milk of magnesia, gastric juice and pure water. Which row is fully correct?
- Asked in CBSE 2023 · 31/1/1 · Q6 · 1 markPick the formula of washing soda.
- Asked in CBSE 2023 · 31/1/1 · Q21(a) · 2 marks(i) X is made from gypsum and sets hard when mixed with water. Name X and give its formula. (ii) How do baking soda and baking powder differ in composition?
- Asked in CBSE 2023 · 31/1/1 · Q21(b) · 2 marksWrite balanced equations for heating (i) blue copper sulphate crystals and (ii) sodium hydrogen carbonate during cooking.
- Asked in CBSE 2023 · 31/1/1 · Q28 · 3 marks(a) Give a remedy for (i) excess stomach acid in indigestion, (ii) a bee sting or nettle sting. (b) Milk has pH 6. Does pH go up or down when it turns into curd? Why?
Metals and Non-metals
27 questions, 39 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q21 · 1 markAmong Pb, Cu, Ag and Al, which conducts electricity poorly?
- Asked in CBSE 2026 · 31/1/1 · Q23 · 1 markElement X begins to float when it reacts with water. Which element is it?
- Asked in CBSE 2026 · 31/1/1 · Q25(a) · 1 markDefine amphoteric oxides.
- Asked in CBSE 2026 · 31/1/1 · Q25(b) · 1 markClassify ZnO, Na₂O and CO₂ by nature.
- Asked in CBSE 2026 · 31/1/1 · Q28(a) · 1 markWhy are carbonate and sulphide ores first changed into oxides before extracting the metal?
- Asked in CBSE 2026 · 31/1/1 · Q28(b) · 1 markGive a reaction where aluminium reduces a metal oxide to the metal.
- Asked in CBSE 2026 · 31/1/1 · Q28(c)(i) · 2 marksHow is copper extracted from Cu₂S? Give the equations.
- Asked in CBSE 2026 · 31/1/1 · Q28(c)(ii) · 2 marks(I) Why can't carbon reduce the oxides of highly reactive metals? (II) Why is solder (lead–tin alloy) used to join electrical wires?
- Asked in CBSE 2025 · 31/1/1 · Q2 · 1 markWhich oxides form when aluminium and magnesium (in that order) burn in air?
- Asked in CBSE 2025 · 31/1/1 · Q5 · 1 markElement A gives electrons to element B to make compound C. Which property does C NOT have: high melting point, good solubility in water, weak attraction between its ions, or conduction when molten/dissolved?
- Asked in CBSE 2025 · 31/1/1 · Q6 · 1 markWhich pair of metals is got by electrolysing their molten chlorides?
- Asked in CBSE 2025 · 31/1/1 · Q7 · 1 markPick the electron-dot scheme that correctly shows how magnesium oxide forms.
- Asked in CBSE 2025 · 31/1/1 · Q27 · 3 marks(a) Show with two examples that displacement reactions help extract metals from the middle of the reactivity series. (b) Why can carbon not reduce the oxides of highly reactive metals?
- Asked in CBSE 2025 · 31/1/1 · Q28(a) · 3 marksDescribe an activity that shows what conditions are needed for iron objects to rust.
- Asked in CBSE 2025 · 31/1/1 · Q28(b) · 3 marks(i) Name two metals that react violently with cold water and give three observations when they are dropped into water. (ii) How would you test the gas given off?
- Asked in CBSE 2024 · 31/1/1 · Q3 · 1 markName, in order, a metal and a non-metal that are liquids at room temperature.
- Asked in CBSE 2024 · 31/1/1 · Q6 · 1 markWhat type of oxides are Al₂O₃ and ZnO?
- Asked in CBSE 2024 · 31/1/1 · Q17 · 1 markAssertion: zinc and nitric acid do not release hydrogen. Reason: HNO₃ is an oxidising agent that turns the H₂ into water and is itself reduced.
- Asked in CBSE 2024 · 31/1/1 · Q37(i) · 1 markIn electrolytic refining of copper, what are the cathode and the anode made of?
- Asked in CBSE 2024 · 31/1/1 · Q37(ii) · 1 markWhich electrolyte solution is used for refining copper electrolytically? Give its formula.
- Asked in CBSE 2024 · 31/1/1 · Q37(iii)(A) · 2 marksExplain how copper is purified when current flows through the electrolytic cell.
- Asked in CBSE 2024 · 31/1/1 · Q37(iii)(B) · 2 marksCopper sulphate solution is in beakers A and B. A zinc strip goes in A and a silver strip in B. What is seen after about 2 hours, and why?
- Asked in CBSE 2023 · 31/1/1 · Q5 · 1 markMetal X is used in the thermite process and burns in air to give amphoteric oxide Y. Name X and Y.
- Asked in CBSE 2023 · 31/1/1 · Q37(a) · 1 markWhat happens when copper is heated in air? Give the equation.
- Asked in CBSE 2023 · 31/1/1 · Q37(b) · 1 markWhy are some metal oxides called amphoteric? Give an example.
- Asked in CBSE 2023 · 31/1/1 · Q37(c)(A) · 2 marksComplete: (i) Na₂O(s) + H₂O(l) → (ii) Al₂O₃ + 2NaOH →
- Asked in CBSE 2023 · 31/1/1 · Q37(c)(B) · 2 marksSulphur burns in oxygen to give a colourless gas. (i) Equation? (ii) Name the gas. (iii) Its nature? (iv) Effect on dry litmus paper?
Carbon and its Compounds
12 questions, 44 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q20 · 1 markGive the functional group of an aldehyde.
- Asked in CBSE 2026 · 31/1/1 · Q24 · 1 markAssertion: carbon shares its valence electrons with carbon or other atoms. Reason: shared electrons count in the outer shells of both atoms, so each attains a noble-gas configuration.
- Asked in CBSE 2026 · 31/1/1 · Q29(a) · 5 marks(i) Explain: (I) covalent compounds conduct electricity poorly; (II) soap gives no lather in hard water; (III) carbon shows catenation but silicon hardly does. (ii) Write equations for (I) oxidation of ethanol with acidified K₂Cr₂O₇ and (II) hydrogenation of ethene.
- Asked in CBSE 2026 · 31/1/1 · Q29(b) · 5 marksEthanol heated with X and a little conc. H₂SO₄ gives a sweet-smelling Y; Y with NaOH gives back ethanol and Z. (i) Identify X, Y, Z. (ii) Role of conc. H₂SO₄? (iii) Equations and names of the reactions.
- Asked in CBSE 2025 · 31/1/1 · Q34(a) · 5 marks(i) Draw two isomers of butene, C₄H₈. (ii) Name: (I) CH₃–CH₂–CH₂–Cl; (II) CH₃–CH₂–CO–CH₃. (iii) Give equations with one needed condition each for: (I) full oxidation of ethanol, (II) hydrogenation of propene, (III) ethanoic acid with ethanol.
- Asked in CBSE 2025 · 31/1/1 · Q34(b) · 5 marks(i) Compound X is a good solvent; with sodium it gives Y and Z, and Z is used to turn vegetable oil into ghee. Identify X, Y, Z with the equation. (ii) Write equations for ethanol (I) burning in air, (II) heated to 443 K with excess conc. H₂SO₄, (III) with acidified potassium dichromate.
- Asked in CBSE 2024 · 31/1/1 · Q4 · 1 markCarbon compounds: (i) conduct electricity well, (ii) conduct electricity poorly, (iii) have strong intermolecular forces, (iv) have weak intermolecular forces. Which pair is correct?
- Asked in CBSE 2024 · 31/1/1 · Q34(A) · 5 marks(i) Define a homologous series. (ii) Why do C₄H₈ boil and melt higher than C₃H₆ or C₂H₄? (iii) Why is there no gradation in chemical properties within the series? (iv) Name and draw the aldehyde and the ketone of formula C₃H₆O.
- Asked in CBSE 2024 · 31/1/1 · Q34(B) · 5 marks(i) Compound X has two carbons and an '-ol' name; give its name and structure. (ii) What forms when X is heated with excess concentrated H₂SO₄ at 443 K? Give the equation with conditions and the acid's role. (iii) Name and draw the electron dot structure of the hydrocarbon formed.
- Asked in CBSE 2023 · 31/1/1 · Q7 · 1 markThree six-carbon rings are drawn: A has only single bonds (each C has 2 H), B has three alternate double bonds (benzene), C has two double bonds. Choose the correct statement.
- Asked in CBSE 2023 · 31/1/1 · Q34(a) · 5 marksAlcohol A, heated with concentrated H₂SO₄ at 443 K, gives unsaturated B (molecular mass 28 u). B adds one mole of H₂ over nickel to give saturated C. (i) Identify A, B, C. (ii) Equation for A → B. (iii) What happens when C burns? (iv) One industrial use of hydrogenation. (v) Products when A reacts with sodium.
- Asked in CBSE 2023 · 31/1/1 · Q34(b) · 5 marks(i) Draw how micelles form when soap acts on oily dirt. (ii) Two tubes with 10 mL hard water each: soap added to X, detergent to Y, both shaken equally. (1) Which foams more and why? (2) Which forms a curdy solid and why?
Life Processes
24 questions, 39 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q1 · 1 markWhich part of a leaf mainly handles the exchange of gases?
- Asked in CBSE 2026 · 31/1/1 · Q5 · 1 markWhich pairing correctly states the job of trypsin and lipase in pancreatic juice?
- Asked in CBSE 2026 · 31/1/1 · Q9 · 1 markAssertion: haemoglobin in red blood cells is the human respiratory pigment. Reason: haemoglobin binds carbon dioxide very strongly.
- Asked in CBSE 2026 · 31/1/1 · Q10 · 2 marksWhat does the diaphragm do in breathing, and where is it located?
- Asked in CBSE 2025 · 31/1/1 · Q8 · 1 markIf less saliva is secreted in the mouth, which conversion is affected?
- Asked in CBSE 2025 · 31/1/1 · Q12 · 1 markGlucose → pyruvate + energy happens at site 'a'; pyruvate → lactic acid + energy happens at site 'b'. Name 'a' and 'b'.
- Asked in CBSE 2025 · 31/1/1 · Q23(a) · 2 marksApart from cutting blood loss, why must a leak in a blood vessel be sealed? Which blood component helps, and how?
- Asked in CBSE 2025 · 31/1/1 · Q23(b) · 2 marks(i) Why is transport in plants slower than in animals? (ii) What does phloem do in plants?
- Asked in CBSE 2025 · 31/1/1 · Q38(a) · 1 markCase: living things need energy for maintenance even at rest, and it comes from food made by autotrophs. Give the name and meaning of the process green plants use to make their food.
- Asked in CBSE 2025 · 31/1/1 · Q38(b) · 1 markWrite the chemical equation for photosynthesis.
- Asked in CBSE 2025 · 31/1/1 · Q38(c)(i) · 2 marksList in order the steps by which desert plants make food.
- Asked in CBSE 2025 · 31/1/1 · Q38(c)(ii) · 2 marksWith reasons, say how the rate of food-making by green plants changes (I) on a cloudy day and (II) when dust blocks the stomata.
- Asked in CBSE 2024 · 31/1/1 · Q11 · 1 markA stoma closes because: (i) CO₂ is needed, (ii) CO₂ is not needed, (iii) guard cells lose water, (iv) guard cells take in water. Which reasons are right?
- Asked in CBSE 2024 · 31/1/1 · Q19 · 1 markAssertion: aquatic animals breathe much faster than land animals. Reason: water holds far more dissolved oxygen than air.
- Asked in CBSE 2024 · 31/1/1 · Q22 · 2 marksGive one function each in human digestion of: (i) hydrochloric acid, (ii) villi, (iii) anal sphincter, (iv) lipase.
- Asked in CBSE 2024 · 31/1/1 · Q29 · 3 marks(i) Why do large multicellular animals need a respiratory pigment? (ii) Give reasons: (a) cartilage rings in the throat, (b) lungs keep some residual air, (c) diaphragm flattens and ribs rise on breathing in, (d) alveoli walls have many blood vessels.
- Asked in CBSE 2023 · 31/1/1 · Q8 · 1 markWhich organism digests food outside its body and then absorbs it?
- Asked in CBSE 2023 · 31/1/1 · Q9 · 1 markWhich statement about the small intestine is NOT correct?
- Asked in CBSE 2023 · 31/1/1 · Q19 · 1 markA: Clotting stops heavy blood loss. R: Clotting is caused by plasma and white blood cells.
- Asked in CBSE 2023 · 31/1/1 · Q23(a) · 2 marksState the type of blood (oxygenated/deoxygenated) and its path for (i) vena cava, (ii) pulmonary artery.
- Asked in CBSE 2023 · 31/1/1 · Q23(b) · 2 marksShow by flow chart how glucose is broken down in a cell for energy (i) with oxygen, (ii) with too little oxygen.
- Asked in CBSE 2023 · 31/1/1 · Q24 · 2 marksWhere in the excretory system are nephrons found? Describe their structure and function.
- Asked in CBSE 2023 · 31/1/1 · Q29(a) · 3 marks(i) Role of ATP in respiration? (ii) What allows enough gas exchange in plants? (iii) On what does the direction of gas diffusion in plants depend?
- Asked in CBSE 2023 · 31/1/1 · Q29(b) · 3 marks(i) What is the stored energy reserve in plants and in animals? (ii) How do desert plants photosynthesise when stomata stay shut by day?
Control and Coordination
12 questions, 22 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q4 · 1 markWhich part of the human brain keeps voluntary movements precise?
- Asked in CBSE 2026 · 31/1/1 · Q8 · 1 markAssertion: a reflex action happens without thinking. Reason: the spinal cord controls most reflex actions.
- Asked in CBSE 2026 · 31/1/1 · Q11(a) · 2 marksGive two differences between chewing food and salivating when food is seen.
- Asked in CBSE 2026 · 31/1/1 · Q14 · 3 marksDifferentiate: (a) nephron and neuron, (b) sensory and motor nerve, (c) consumers and decomposers.
- Asked in CBSE 2025 · 31/1/1 · Q9 · 1 markWhich plant hormone makes shoot cells on the shaded side (away from light) elongate more?
- Asked in CBSE 2025 · 31/1/1 · Q29 · 3 marksTouch-me-not leaves fold and droop when touched, though plants have no nerves or muscles. (a) How is the message passed? (b) What lets plant cells produce the visible movement? (c) How does this movement differ from a pea tendril's movement?
- Asked in CBSE 2024 · 31/1/1 · Q10 · 1 markAt which site of a nerve cell is the electrical impulse changed into a chemical signal: axon, dendrites, neuromuscular junction, or cell body?
- Asked in CBSE 2024 · 31/1/1 · Q23(A) · 2 marksCompare the folding of a touch-me-not (sensitive plant) leaf with the downward growth of roots.
- Asked in CBSE 2024 · 31/1/1 · Q23(B) · 2 marksWhich hormone controls carbohydrate, protein and fat metabolism, and which gland makes it? Why should our salt be iodised?
- Asked in CBSE 2024 · 31/1/1 · Q30 · 3 marksWhat is a reflex action? Draw a flow chart of the pathway for a reflex like sneezing.
- Asked in CBSE 2023 · 31/1/1 · Q11 · 1 markWhich statement about tropic movement in plants is correct?
- Asked in CBSE 2023 · 31/1/1 · Q22 · 2 marks(a) What does insulin do to blood sugar, and which disease results from its shortage? (b) What controls when and how much insulin is released?
How do Organisms Reproduce?
15 questions, 46 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q2 · 1 markA diagram shows a single amoeba-like cell whose nucleus divides and then the cell splits into two daughter cells. Name this mode of reproduction.
- Asked in CBSE 2026 · 31/1/1 · Q3 · 1 markWhat is true of Spirogyra, Leishmania and Hydra together?
- Asked in CBSE 2026 · 31/1/1 · Q11(b) · 2 marksGive two differences between pollination and fertilisation.
- Asked in CBSE 2026 · 31/1/1 · Q12 · 2 marksDraw pollen germinating on the pistil of a flower and label (a) the part that receives pollen and (b) the structure that takes the male germ cell to the female germ cell.
- Asked in CBSE 2026 · 31/1/1 · Q16(a) · 5 marksSay what would follow in each case: (i) water holding a bacterial population warms up due to global warming; (ii) a sperm meets the egg in the oviduct; (iii) a flower has only a pistil (no stamens), so it cannot self-pollinate; (iv) the egg of a human female is not fertilised; (v) a seed in soil gets enough water and air.
- Asked in CBSE 2026 · 31/1/1 · Q16(b) · 5 marksSay what happens when: (i) bread-mould spores are released from their sporangia; (ii) Bryophyllum leaves drop onto moist soil; (iii) pollen lands on the stigma of an unrelated species; (iv) a Copper-T is fitted in the uterus; (v) Spirogyra breaks into pieces after maturing.
- Asked in CBSE 2025 · 31/1/1 · Q10 · 1 markWhich are true for a bisexual flower: (i) has both stamens and pistil; (ii) has only stamens or only pistil; (iii) can be self- or cross-pollinated; (iv) cannot form fruit by itself?
- Asked in CBSE 2025 · 31/1/1 · Q22 · 2 marksDraw labelled sketches of the stages of budding in Hydra.
- Asked in CBSE 2025 · 31/1/1 · Q35(a) · 5 marks(i) Give the function of the (I) ovary, (II) fallopian tube, (III) uterus in human females. (ii) Briefly describe two birth-control methods used by men.
- Asked in CBSE 2025 · 31/1/1 · Q35(b) · 5 marks(i) How do self-pollination and cross-pollination differ? (ii) In the diagram of a pistil during fertilisation, identify A, B, C and give one function of each.
- Asked in CBSE 2024 · 31/1/1 · Q16 · 1 markWhich organism reproduces asexually by multiple fission: yeast, Leishmania, Paramoecium or Plasmodium?
- Asked in CBSE 2024 · 31/1/1 · Q35(A) · 5 marks(i) Give three methods/devices women use to avoid pregnancy and a side effect of each. (ii) In a woman, what happens if (a) fertilisation occurs, (b) the egg is not fertilised?
- Asked in CBSE 2024 · 31/1/1 · Q35(B) · 5 marks(i) Draw spore formation in Rhizopus, labelling its reproductive and non-reproductive parts; why does it not grow on dry bread? (ii) Name and explain how Hydra reproduces.
- Asked in CBSE 2023 · 31/1/1 · Q12 · 1 markFind the wrong pair of plant and vegetative part used: Bryophyllum–leaf, potato–stem, money-plant–stem, rose–root.
- Asked in CBSE 2023 · 31/1/1 · Q35 · 5 marks(a) Which parts of a bisexual flower take no direct part in reproduction? (b) Differentiate self- and cross-pollination; give two uses of pollination. (c) What do ovules and ovary become after fertilisation?
Heredity
19 questions, 27 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q6 · 1 markFor humans, which hold: (i) X-bearing gamete from the mother, (ii) X-bearing gamete from the father, (iii) Y-bearing gamete from the father? Pick the option naming the correct ones.
- Asked in CBSE 2026 · 31/1/1 · Q15(a) · 1 markMendel crossed tall and short pea plants and got only tall plants in F1. Why?
- Asked in CBSE 2026 · 31/1/1 · Q15(b) · 1 markIn the tall × short pea cross, how did Mendel get the F2 generation?
- Asked in CBSE 2026 · 31/1/1 · Q15(c)(i) · 2 marksGive one difference between a dominant and a recessive trait.
- Asked in CBSE 2026 · 31/1/1 · Q15(c)(ii) · 2 marksState two things Mendel noticed about the F1 plants of the tall × short cross.
- Asked in CBSE 2025 · 31/1/1 · Q11 · 1 markPea plants RRyy (round, green) are crossed with rrYY (wrinkled, yellow). What seeds do F1 plants show?
- Asked in CBSE 2025 · 31/1/1 · Q18 · 1 markAssertion: a human baby has all the basic human features. Reason: the baby looks exactly like its parents with very little variation.
- Asked in CBSE 2025 · 31/1/1 · Q30 · 3 marks(a) What are chromosomes? (b) In sexually reproducing organisms, how does the amount of DNA stay constant from one generation to the next?
- Asked in CBSE 2024 · 31/1/1 · Q8 · 1 markPick the true statements: a baby's sex is decided by (i) what comes from the mother, (ii) what comes from the father; (iii) a boy is more likely than a girl; (iv) sex is fixed at fertilisation when the zygote forms.
- Asked in CBSE 2024 · 31/1/1 · Q38(i) · 1 markMendel crossed pure tall with pure short pea plants. State two observations he made on the F₁ plants.
- Asked in CBSE 2024 · 31/1/1 · Q38(ii) · 1 markGive one way a dominant trait differs from a recessive trait.
- Asked in CBSE 2024 · 31/1/1 · Q38(iii)(A) · 2 marksFor RRYY (round yellow) × rryy (wrinkled green), F₂ showed 4 kinds of seeds. How was F₂ obtained, what is the ratio of the two parental types, and what was concluded?
- Asked in CBSE 2024 · 31/1/1 · Q38(iii)(B) · 2 marksJustify: a trait can be passed on yet stay hidden.
- Asked in CBSE 2023 · 31/1/1 · Q10 · 1 markWhich statement about a gene is correct?
- Asked in CBSE 2023 · 31/1/1 · Q18 · 1 markA: Genes from the parents decide a child's sex. R: A boy gets his X chromosome from his father.
- Asked in CBSE 2023 · 31/1/1 · Q38(a) · 1 markApart from seed shape and seed colour, give two pairs of contrasting pea characters Mendel used.
- Asked in CBSE 2023 · 31/1/1 · Q38(b) · 1 markDifferentiate dominant and recessive traits.
- Asked in CBSE 2023 · 31/1/1 · Q38(c)(A) · 2 marksRound yellow peas crossed with wrinkled green; F₁ selfed. Give the F₂ ratio of seed types and what it shows.
- Asked in CBSE 2023 · 31/1/1 · Q38(c)(B) · 2 marksCross pure violet (VV) with pure white (vv) pea plants. Show the F₁ and F₂ progeny.
Light – Reflection and Refraction
22 questions, 43 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q30 · 1 markA convex lens with f = 15 cm makes a real image equal in size to the object. Give the object and image positions.
- Asked in CBSE 2026 · 31/1/1 · Q33 · 2 marks(a) From the ray diagram, which type of lens is used? (b) A real image forms 30 cm from the lens and is twice the object's size. Where was the object?
- Asked in CBSE 2026 · 31/1/1 · Q38(a) · 1 markAn object is 40 cm from a convex lens of focal length 20 cm. Give the image position and nature.
- Asked in CBSE 2026 · 31/1/1 · Q38(b) · 1 markDraw the ray diagram for an object between the optical centre and the focus of a concave lens.
- Asked in CBSE 2026 · 31/1/1 · Q38(c)(i) · 2 marksA convex lens (f = 30 cm) and a concave lens (f = 15 cm) are in contact. Find the combined focal length and power.
- Asked in CBSE 2026 · 31/1/1 · Q38(c)(ii) · 2 marksA concave lens of focal length 2 m touches a convex lens of focal length 1.5 m. Is the pair convex or concave in effect? Why?
- Asked in CBSE 2025 · 31/1/1 · Q13 · 1 markMirror X focuses sunlight in a solar furnace; mirror Y is a vehicle's side (rear-view) mirror. Which statements are true: (i) X gives a real, small image at its focus; (ii) Y gives a virtual, small, erect image; (iii) X gives a virtual, small, erect image; (iv) Y gives a real, small image at its focus?
- Asked in CBSE 2025 · 31/1/1 · Q24 · 2 marksUsing the lens formula, locate the image of an object kept 60 cm from a diverging (concave) lens whose focal length is 30 cm.
- Asked in CBSE 2025 · 31/1/1 · Q31 · 3 marksDraw ray diagrams for a convex mirror with the object (i) at infinity and (ii) anywhere between infinity and the pole P; state the image's nature, position and size.
- Asked in CBSE 2025 · 31/1/1 · Q36(a) · 5 marks(i) Lens X has power -2.5 D. Name it, find its focal length in cm, and say which eye defect it corrects. (ii) A lens gives magnification m = -2 for an object 20 cm from its optical centre. Using the sign convention, give the image's (I) nature, (II) size vs object, (III) position, (IV) sign of height. (iii) Lenses A and B have focal lengths of 10 cm and 20 cm. Which converges/diverges light more, and why?
- Asked in CBSE 2025 · 31/1/1 · Q36(b) · 5 marks(i) Draw the path of a ray going obliquely from air into a rectangular glass slab and out again. (ii) State Snell's law. (iii) Compare the virtual images of a convex and a concave lens by (I) where the object must be and (II) magnification.
- Asked in CBSE 2024 · 31/1/1 · Q12 · 1 markWhere must an object be kept in front of a convex lens so that a real image of equal size forms on a screen?
- Asked in CBSE 2024 · 31/1/1 · Q24 · 2 marksA convex mirror has focal length 15 cm and an object is 10 cm in front of it. Locate the image.
- Asked in CBSE 2024 · 31/1/1 · Q39(i) · 1 markConcave mirrors: A (f 20 cm, object at 45 cm), B (f 15 cm, object at 30 cm), C (f 30 cm, object at 20 cm). Which gives a diminished image? Justify.
- Asked in CBSE 2024 · 31/1/1 · Q39(ii) · 1 markMirror B has f = 15 cm with the object at 30 cm. Give two properties of the image.
- Asked in CBSE 2024 · 31/1/1 · Q39(iii)(A) · 2 marksMirror C has f = 30 cm with the object at 20 cm. Give the image's nature and size and justify with a ray diagram.
- Asked in CBSE 2024 · 31/1/1 · Q39(iii)(B) · 2 marksAn object is 18 cm from a concave mirror of focal length 12 cm. Locate the image.
- Asked in CBSE 2023 · 31/1/1 · Q30 · 3 marksObject AB stands in front of a convex mirror (pole P; F marked R and centre C behind it). Ray 1 goes parallel to the axis; ray 2 heads towards C. (a) Complete the ray diagram. (b) Give nature, position and size of the image. (c) Sign of image distance?
- Asked in CBSE 2023 · 31/1/1 · Q39(a) · 1 markGive two uses of concave mirrors.
- Asked in CBSE 2023 · 31/1/1 · Q39(b) · 1 markThe focus of a concave mirror is 15 cm from it. Find the radius of curvature.
- Asked in CBSE 2023 · 31/1/1 · Q39(c)(A) · 2 marksDraw the ray diagram for an object placed between the pole and focus of a concave mirror.
- Asked in CBSE 2023 · 31/1/1 · Q39(c)(B) · 2 marksA 10 cm object is 100 cm in front of a concave mirror and its image forms at the object's own position. Find (i) focal length, (ii) magnification with sign.
The Human Eye and the Colourful World
10 questions, 18 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q31 · 1 markWhat happens in the eye when you look at something very near?
- Asked in CBSE 2026 · 31/1/1 · Q32 · 1 markAssertion: white light leaving a prism splits into a seven-colour spectrum. Reason: scattering makes red bend least and violet bend most.
- Asked in CBSE 2026 · 31/1/1 · Q35 · 3 marksA person cannot read a book held nearer than 1 m. Name the defect and draw ray diagrams of the defect and its correction.
- Asked in CBSE 2025 · 31/1/1 · Q14 · 1 markAn elderly person's ciliary muscles have weakened and the eye lens has become less flexible. Name the defect 'a' and the corrective lens 'b'.
- Asked in CBSE 2024 · 31/1/1 · Q13 · 1 markName the light-sensitive screen of the eye on which the eye lens forms the image.
- Asked in CBSE 2024 · 31/1/1 · Q20 · 1 markAssertion: a rainbow is a natural spectrum of sunlight. Reason: it forms when the sun is overhead and droplets are in the air.
- Asked in CBSE 2024 · 31/1/1 · Q31 · 3 marksFrom the eye diagram: (i) name the defect and give the reason, (ii) give two causes, (iii) draw how it is corrected.
- Asked in CBSE 2023 · 31/1/1 · Q25(a) · 2 marksA narrow beam of white light XY enters glass prism ABC; a screen PQ is placed beyond the prism. Show the emergent beam on the screen, name the phenomenon and give its cause.
- Asked in CBSE 2023 · 31/1/1 · Q25(b) · 2 marksWith age, the eye's power to see both near and far objects falls. (i) Why? (ii) Name the defect. (iii) Draw the corrective lens arrangement.
- Asked in CBSE 2023 · 31/1/1 · Q31 · 3 marksWhy: (a) danger lights at airports and on tall buildings are red; (b) the sky looks dark to people flying very high; (c) a light beam is visible through a colloid?
Electricity
15 questions, 45 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q34(a) · 2 marksA wire of radius 0.01 cm and length 1.0 cm has resistance 7 Ω. Find its resistivity.
- Asked in CBSE 2026 · 31/1/1 · Q34(b) · 2 marksA heater rated 220 V, 11 A is run on 200 V. Find the power it uses.
- Asked in CBSE 2026 · 31/1/1 · Q39(a) · 5 marks(i) Changing a conductor's length or cross-section alters its resistance but not its resistivity — why? (ii) Why are heating elements of toasters and irons made of alloys and not pure metals? (iii) Define the SI unit of electric current.
- Asked in CBSE 2026 · 31/1/1 · Q39(b) · 5 marks(i) How many 8 Ω bulbs in parallel make a 4 V battery give 2 A? (ii) Which device measures current and how is it connected? (iii) State Joule's law of heating.
- Asked in CBSE 2025 · 31/1/1 · Q25(a) · 2 marksA wire with resistance R is divided into 3 equal lengths, which are then connected in parallel. Find the combined resistance.
- Asked in CBSE 2025 · 31/1/1 · Q25(b) · 2 marksDefine electric power. When is the power used in a circuit equal to 1 watt?
- Asked in CBSE 2025 · 31/1/1 · Q32 · 3 marksA 15 V battery, key and ammeter are in series with two groups: 10 Ω and 15 Ω in parallel, and 60 Ω and 40 Ω in parallel. Find (a) total resistance, (b) current supplied by the battery, (c) voltage across the 10 Ω–15 Ω group.
- Asked in CBSE 2025 · 31/1/1 · Q33 · 3 marks(a) Relate resistance and resistivity for a cylindrical wire of length l and cross-section area A, and obtain the unit of resistivity in SI. (b) Give the reason alloys are used in heating appliances.
- Asked in CBSE 2024 · 31/1/1 · Q25(A) · 2 marksUsing three 6 Ω resistors, how do you get a total of 9 Ω? Justify.
- Asked in CBSE 2024 · 31/1/1 · Q25(B) · 2 marksA 6 V battery drives current through 1 Ω and 2 Ω in series. Find the power used in the 2 Ω resistor.
- Asked in CBSE 2024 · 31/1/1 · Q36(A) · 5 marks(i) Define electric power and write it using V and R. (ii) A 220 V oven uses 11 units of energy in 5 h. Find (a) its power, (b) its current, (c) its resistance when red hot.
- Asked in CBSE 2024 · 31/1/1 · Q36(B) · 5 marks(i) Relate R to resistivity ρ for a wire of length l and cross-section A and derive the SI unit of ρ. (ii) A 3 m wire of area 4×10⁻⁷ m² has resistance 60 Ω; find ρ. (iii) How does ρ change if this wire is stretched to double length? Why?
- Asked in CBSE 2023 · 31/1/1 · Q13 · 1 markFour 8 Ω resistors give Rs in series and Rp in parallel. Find Rs/Rp.
- Asked in CBSE 2023 · 31/1/1 · Q15 · 1 markA voltmeter scale runs 0 to 3 V with 1.5 V at the top; between 0 and 1.5 there are 10 equal divisions. The needle is 2 small divisions past 1.5. Find the least count and the reading.
- Asked in CBSE 2023 · 31/1/1 · Q36 · 5 marks(a) An iron uses 880 W at maximum heating and 330 W at minimum, on 220 V. Find current and resistance in each case. (b) What is the heating effect of current? (c) Derive the heat produced in a resistor in time t.
Magnetic Effects of Electric Current
15 questions, 28 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q36 · 3 marks(a) Describe an activity showing that a current-carrying conductor in a magnetic field feels a force. (b) You sit facing the front wall; an electron beam travelling horizontally from the back wall to the front wall is pushed to your right by a strong magnetic field. Find the field direction.
- Asked in CBSE 2026 · 31/1/1 · Q37 · 3 marks(a) Show that the field pattern of a current-carrying wire depends on the wire's shape. (b) A straight wire AB carries current upward; points X, Y, Z lie on a line to one side at increasing distance. Where is the field strongest, and why?
- Asked in CBSE 2025 · 31/1/1 · Q19 · 1 markAssertion: magnetic field lines never intersect. Reason: at a crossing point a compass needle would have to point in two directions at once.
- Asked in CBSE 2025 · 31/1/1 · Q39(a) · 1 markCase: homes get mains power at 220 V between live and neutral wires. What colours are the insulation of the supply wires?
- Asked in CBSE 2025 · 31/1/1 · Q39(b) · 1 markWhat current rating should a 220 V circuit have to run a 1 kW electric iron?
- Asked in CBSE 2025 · 31/1/1 · Q39(c)(i) · 2 marksWhat does the earth wire do, and how does it help with appliances like an electric iron?
- Asked in CBSE 2025 · 31/1/1 · Q39(c)(ii) · 2 marksGive two precautions against electrical accidents and how each prevents damage.
- Asked in CBSE 2024 · 31/1/1 · Q14 · 1 markChoose the diagram that shows the field pattern inside a solenoid carrying current.
- Asked in CBSE 2024 · 31/1/1 · Q26 · 2 marks(i) Why can two magnetic field lines never cross? (ii) How is a uniform field shown? Sketch it.
- Asked in CBSE 2024 · 31/1/1 · Q32 · 3 marksName and state the rule for the direction of (i) the field around a straight wire with current, (ii) the force on a straight current-carrying wire kept at right angles to a magnetic field.
- Asked in CBSE 2023 · 31/1/1 · Q14 · 1 markDomestic wiring rated 15 A is meant for which appliances?
- Asked in CBSE 2023 · 31/1/1 · Q16 · 1 markTwo horizontal parallel wires AB (top) and CD (bottom) carry equal current I in the same direction. What is the net magnetic field at P, midway between them?
- Asked in CBSE 2023 · 31/1/1 · Q20 · 1 markA: More turns in a circular coil give a stronger field at its centre. R: Current in every turn flows the same way, so the fields of the turns add.
- Asked in CBSE 2023 · 31/1/1 · Q32(a) · 3 marks(i) Which rule gives the force on a current-carrying conductor in a magnetic field? State it. (ii) An electron enters a field (lines left to right) (i) at right angles, (ii) at a slant, (iii) along the lines. Where is the force maximum and minimum? Why?
- Asked in CBSE 2023 · 31/1/1 · Q32(b) · 3 marks(i) Draw field lines of (1) a current-carrying solenoid and (2) a bar magnet. (ii) Give two differences between these fields.
Our Environment
13 questions, 25 marks across 4 papers
- Asked in CBSE 2026 · 31/1/1 · Q7 · 1 markWhich group of items is non-biodegradable?
- Asked in CBSE 2026 · 31/1/1 · Q13 · 3 marksA pyramid has levels (i) producers, (ii) primary, (iii) secondary and (iv) tertiary consumers. (a) Place deer, grass, lion, snake and rabbit on these levels. (b) Why do primary consumers get more energy than secondary consumers? (c) Why is the pyramid's base wide?
- Asked in CBSE 2025 · 31/1/1 · Q15 · 1 markWhich of these sets (members listed in any order) cannot be arranged as a chain of eater and eaten: (i) lion, grass, wolf, rabbit; (ii) man, fish, plankton, grasshopper; (iii) frog, hawk, grasshopper, snake, grass; (iv) tiger, grass, wolf, snake?
- Asked in CBSE 2025 · 31/1/1 · Q16 · 1 markAbout what percentage of sunlight falling on green leaves on land is NOT turned into food energy?
- Asked in CBSE 2025 · 31/1/1 · Q20 · 1 markAssertion: atmospheric ozone started falling sharply during the 1980s. Reason: ozone forms when an oxygen atom joins an O₂ molecule.
- Asked in CBSE 2025 · 31/1/1 · Q26 · 2 marksExplain how heavy use of farm chemicals and pesticides harms the environment.
- Asked in CBSE 2024 · 31/1/1 · Q15 · 1 markIn which listed food chain is the second trophic level (herbivore) absent: grass-goat-lion; zooplankton-phytoplankton-small fish-large fish; tiger-grass-snake-frog; grasshopper-grass-snake-frog-eagle?
- Asked in CBSE 2024 · 31/1/1 · Q18 · 1 markAssertion: harmful chemicals collect most in the top trophic level. Reason: such chemicals are sprayed on crops against pests and diseases.
- Asked in CBSE 2024 · 31/1/1 · Q33(A) · 3 marksIn Plants → Deer → Lion, what happens to levels 1 and 3 if all deer are removed? Would lions be hit the same way if they were part of a food web? Explain.
- Asked in CBSE 2024 · 31/1/1 · Q33(B) · 3 marksGas X is poisonous yet does a vital job high in the atmosphere. Name it and its job, the chemical blamed for its decline, and the international step taken to protect its layer.
- Asked in CBSE 2023 · 31/1/1 · Q26 · 2 marksHow do harmful chemicals build up more and more at each trophic level of a food chain?
- Asked in CBSE 2023 · 31/1/1 · Q33(a) · 3 marks(i) Why is a kitchen garden an artificial ecosystem but a forest natural? (ii) Name two things to keep in mind to make a home ecosystem self-sustaining, with reasons.
- Asked in CBSE 2023 · 31/1/1 · Q33(b) · 3 marks(i) Make a four-level food chain from hawk, snake, plants, rat. (ii) Producers pass 20,000 J to the second trophic level. How much energy goes from the third to the fourth level?