Science Important Questions Class 10 CBSE 2026 — Chapter Wise
Class 10 Science important questions 2026 — Physics, Chemistry, Biology chapter-wise expected questions for CBSE board exam.
CBSE Class 10 Science: 80 marks theory + 20 marks internal assessment. Physics (Electricity + Light + Magnetic Effects) carries the most marks. Below are the most expected questions from each chapter based on 2018–2025 paper analysis.
Chapter-Wise Marks Distribution
| Chapter | Approx Marks | Question Types |
|---|---|---|
| Chemical Reactions & Equations | 6–8 | Balancing, reaction types, activity-based |
| Acids, Bases & Salts | 5–7 | pH, indicators, reactions, properties |
| Metals & Non-metals | 5–7 | Reactivity series, extraction, ionic bonding |
| Carbon & Its Compounds | 6–8 | Homologous series, IUPAC naming, properties |
| Life Processes | 8–10 | Diagrams, processes, differences |
| Control & Coordination | 5–7 | Neuron diagram, reflex arc, hormones |
| How Do Organisms Reproduce | 5–6 | Types, flower diagram, contraception |
| Heredity & Evolution | 5–6 | Mendel's cross, sex determination, evolution |
| Light | 10–12 | Ray diagrams, numericals, mirror/lens formula |
| Electricity | 13–15 | Numericals (V=IR, P=VI), circuit diagrams |
| Magnetic Effects | 5–6 | Fleming's rules, motor, generator |
| Sources of Energy | 3–4 | Conventional vs non-conventional |
| Our Environment | 3–4 | Food chains, ozone, biodegradable |
Chemistry — Most Expected Questions
Chemical Reactions & Equations
| Question | Marks |
|---|---|
| Write balanced chemical equations for: (a) burning of magnesium in air, (b) reaction of zinc with dilute HCl, (c) decomposition of ferrous sulphate on heating | 3 |
| What is a combination reaction? Give 2 examples with balanced equations. | 3 |
| Differentiate between exothermic and endothermic reactions with examples. | 3 |
| What is corrosion? How can you prevent corrosion of iron? | 3 |
| What is rancidity? How can it be prevented? | 2 |
| What happens when lead nitrate is heated? Write the balanced equation and identify the reaction type. | 3 |
Carbon & Its Compounds
| Question | Marks |
|---|---|
| What is a homologous series? Give 3 properties. Write the first 5 members of the alkane series. | 5 |
| What are the properties of ethanol? What happens when ethanol reacts with sodium? | 3 |
| Write the IUPAC names of: CH₃CHO, CH₃COOH, CH₃CH₂OH, CH₃COCH₃ | 2 |
| What is the difference between saturated and unsaturated hydrocarbons? How can you test for unsaturation? | 3 |
| Explain the cleansing action of soap with diagram. | 5 |
Physics — Most Expected Questions
Electricity (Highest Weightage)
| Question | Marks |
|---|---|
| State Ohm's law. Draw V-I graph for a metallic conductor. What does the slope represent? | 3 |
| Three resistors of 2Ω, 3Ω, and 6Ω are connected in parallel. Find the equivalent resistance and current from a 12V battery. | 5 |
| Derive the expression for equivalent resistance when resistors are connected in series. | 3 |
| An electric heater of 1000W is used for 2 hours daily. Find the electricity bill for 30 days at ₹5 per unit. | 3 |
| What is the difference between resistors in series and parallel? Draw circuit diagrams for each. | 5 |
| What is electrical resistivity? On what factors does resistance of a conductor depend? | 3 |
| State Joule's law of heating. Give 2 applications. | 3 |
Light — Reflection & Refraction
| Question | Marks |
|---|---|
| Draw ray diagrams for image formation by concave mirror when object is: (a) at infinity, (b) between C and F, (c) at F. | 5 |
| A concave mirror produces 3 times magnified real image of an object at 10 cm. Find the focal length. | 3 |
| Define: (a) power of a lens, (b) 1 dioptre. A lens has power −2.5D. What is its focal length and nature? | 3 |
| Explain why a ray of light bends when passing from one medium to another. State Snell's law. | 3 |
| Draw ray diagram for image formed by convex lens when object is between F and 2F. | 3 |
| What is total internal reflection? State 2 conditions and give 2 examples. | 3 |
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Life Processes
| Question | Marks |
|---|---|
| Draw a labelled diagram of the human heart. Describe the flow of blood through the heart. | 5 |
| What is the role of the following in human digestive system: (a) HCl, (b) bile, (c) villi, (d) pancreatic enzymes? | 5 |
| Draw a labelled diagram of nephron. Explain the process of urine formation. | 5 |
| Differentiate between: (a) arteries and veins, (b) aerobic and anaerobic respiration. | 3 |
| What is transpiration? What is its significance? | 2 |
| Draw a diagram showing stomata. Explain how stomata open and close. | 3 |
Control & Coordination
| Question | Marks |
|---|---|
| Draw a labelled diagram of a neuron. What are the functions of: dendrite, axon, nerve ending? | 5 |
| What is a reflex arc? Draw a diagram and explain the reflex action with an example. | 5 |
| Name 3 plant hormones. State the function of each. | 3 |
| Differentiate between nervous control and hormonal control. | 3 |
| What is the function of: (a) cerebrum, (b) cerebellum, (c) medulla? | 3 |
Heredity & Evolution
| Question | Marks |
|---|---|
| Explain Mendel's monohybrid cross with a Punnett square. State the phenotypic and genotypic ratio. | 5 |
| How is the sex of a child determined in humans? Explain with a diagram. | 3 |
| What are homologous organs? Give 2 examples. What do they indicate? | 3 |
| Differentiate between acquired and inherited traits with examples. | 3 |
Magnetic Effects & Sources of Energy
| Question | Marks |
|---|---|
| State Fleming's left-hand rule. Explain the working of an electric motor with diagram. | 5 |
| What is electromagnetic induction? State Fleming's right-hand rule. | 3 |
| Differentiate between AC and DC. Why is AC preferred for long-distance transmission? | 3 |
| What are the advantages and limitations of solar energy? | 3 |
| Differentiate between nuclear fission and nuclear fusion. | 3 |
Answer Writing Tips
- Chemical equations: Always balance. Always write state symbols (s, l, g, aq). Write conditions above arrow.
- Physics numericals: Given → To Find → Formula → Substitution → Answer with units.
- Ray diagrams: Use ruler. Label all points (F, C, P, O, I). Show arrow on rays for direction.
- Biology diagrams: Large, neat, pencil drawing, pen labelling. Minimum 6 labels.
- Differences: Always use table format with 4–5 points. Never write in paragraph.
Questions based on analysis of CBSE Class 10 Science papers (2018–2025) and 2026 sample paper. Not all questions will appear — use this as a revision priority guide. Always complete full NCERT before using this list. Last updated: February 2026.
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Start preparing — freeFrequently Asked Questions
Which chapters are most important for Class 10 Science?
Top 5 by marks: Electricity (13-15 marks), Light (10-12 marks), Chemical Reactions & Equations (6-8 marks), Carbon & Its Compounds (6-8 marks), Life Processes (8-10 marks). These 5 chapters cover 60%+ of the paper. Master them first.
How many questions come from NCERT in Science?
Almost all — 90%+ of board Science questions are based on NCERT textbook content. In-text questions, back exercises, and activity-based questions are frequently tested. NCERT Exemplar adds slightly harder MCQs. Reference books are NOT needed for boards — NCERT is sufficient.
Are diagrams important in Class 10 Science?
Very important — 10-15 marks come from diagrams. Must-draw: electric circuit diagrams, ray diagrams (mirror & lens — 6 cases each), human heart, nephron, neuron, flower structure, magnetic field lines. Always use pencil for drawing and pen for labelling.
How to score full marks in Class 10 Science?
Strategy: (1) Complete NCERT thoroughly — every example, every in-text question. (2) Solve 10 previous year papers under timed conditions. (3) Master all diagrams. (4) Learn chemical equations with balancing and state symbols. (5) Practise Physics numericals daily. (6) Write answers in points with key terms underlined.