📚 Jnaanangkur — The Learning Hub
CLASS 10 SCIENCE
Complete Q&A Guide
Chapter-wise Q&A · PYQs · Model Papers · Exam Tips · Memory Tricks
For CBSE Board Students | Academic Year 2026–27
✅ VSA / SA / LA Questions
✅ NCERT + PYQs
✅ Case Studies
✅ Assertion-Reason
✅ 3 Model Papers
✅ Diagram Guide
💙 Dear Class 10 Student — A Warm Welcome!
Congratulations on picking up this guide — that first step already puts you ahead! Class 10 Board Exams can feel overwhelming, but with the right resources and a smart study plan, scoring 90+ in Science is absolutely achievable.
- Chapter-wise Important Q&A (VSA, SA, LA)
- NCERT-based & Previous Year Questions (PYQs)
- Key Definitions, Formulae & Concepts
- Case Study & Assertion-Reason Questions
- 3 Full-Length Model Papers with Answer Keys
- Exam Tips, Memory Tricks & Common Mistakes
CBSE Class 10 Science — Syllabus at a Glance
Unit-wise chapter distribution with marks allocation
| Unit | Chapter | Topics | Marks |
|---|---|---|---|
| I — Chemical Substances | Ch 1: Chemical Reactions & Equations | Types of reactions, balancing equations, oxidation/reduction | 25 |
| Ch 2: Acids, Bases & Salts | pH, neutralization, salts, bleaching powder | ||
| Ch 3: Metals & Non-Metals | Properties, reactivity series, corrosion | ||
| Ch 4: Carbon & its Compounds | Organic chemistry, homologous series, soaps & detergents | ||
| II — World of Living | Ch 6: Life Processes | Nutrition, respiration, transportation, excretion | 25 |
| Ch 7: Control & Coordination | Nervous system, hormones, reflexes | ||
| Ch 8: How do Organisms Reproduce? | Asexual & sexual reproduction | ||
| Ch 9: Heredity | Mendel's laws, genetics, evolution basics | ||
| III — Natural Phenomena | Ch 10: Light — Reflection & Refraction | Mirrors, lenses, image formation | 12 |
| Ch 11: Human Eye & Colourful World | Defects of vision, dispersion, scattering | ||
| IV — Effects of Current | Ch 12: Electricity | Ohm's law, resistance, circuits, power | 13 |
| Ch 13: Magnetic Effects of Current | Fleming's rules, motors, generators | ||
| V — Natural Resources | Ch 15: Our Environment | Ecosystems, food chains, ozone depletion | 5 |
🧪 Chapter 1: Chemical Reactions and Equations
Types of reactions · Balancing equations · Oxidation & Reduction · Corrosion · Rancidity
📖 Key Concepts & Definitions
| Term | Definition |
|---|---|
| Chemical Reaction | A process in which one or more substances (reactants) are converted into new substances (products) with different properties. |
| Chemical Equation | A symbolic representation of a chemical reaction using chemical formulae of reactants and products. |
| Balanced Equation | An equation where the number of atoms of each element is equal on both sides. |
| Oxidation | Gain of oxygen or loss of hydrogen (or loss of electrons). |
| Reduction | Loss of oxygen or gain of hydrogen (or gain of electrons). |
| Redox Reaction | A reaction where oxidation and reduction occur simultaneously. |
| Exothermic Reaction | A reaction that releases heat energy to the surroundings (ΔH < 0). |
| Endothermic Reaction | A reaction that absorbs heat energy from the surroundings (ΔH > 0). |
| Precipitate | An insoluble solid that separates out from a solution during a chemical reaction. |
| Corrosion | A slow process where metals are degraded by reaction with moisture, oxygen, or other substances. |
| Rancidity | Oxidation of fats and oils in food that changes its smell and taste. |
⚗️ Types of Chemical Reactions
| Type | Example |
|---|---|
| Combination (A + B → AB) | CaO + H₂O → Ca(OH)₂ |
| Decomposition (AB → A + B) | 2H₂O → 2H₂ + O₂ (electrolysis) |
| Displacement (A + BC → AC + B) | Fe + CuSO₄ → FeSO₄ + Cu |
| Double Displacement (AB + CD → AD + CB) | Na₂SO₄ + BaCl₂ → BaSO₄↓ + 2NaCl |
| Thermal Decomposition | CaCO₃ → CaO + CO₂↑ (on heating) |
| Photochemical Decomposition | 2AgCl → 2Ag + Cl₂ (in sunlight) |
| Precipitation Reaction | AgNO₃ + NaCl → AgCl↓ + NaNO₃ |
📝 Must-Know Equations
🔬 Important Chemical Equations
- Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy
- Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
- Thermite Reaction: Fe₂O₃ + 2Al → Al₂O₃ + 2Fe (highly exothermic)
- Electrolysis of water: 2H₂O → 2H₂ + O₂
- Burning of magnesium: 2Mg + O₂ → 2MgO
- Rusting of iron: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O
- Quick lime + water: CaO + H₂O → Ca(OH)₂ (slaking of lime)
❓ Very Short Answer Questions (1 Mark)
1 MarkWhat is a chemical equation?›
A chemical equation is a symbolic representation of a chemical reaction where reactants are written on the left and products on the right, separated by an arrow (→).
1 MarkDefine oxidation.›
Oxidation is the process of gain of oxygen, loss of hydrogen, or loss of electrons by a substance in a chemical reaction.
1 MarkWhat is meant by a precipitation reaction? Give one example.›
A reaction in which an insoluble solid (precipitate) is formed when two solutions are mixed.
Example: Na₂SO₄ + BaCl₂ → BaSO₄↓ + 2NaCl (BaSO₄ is the white precipitate.)
Example: Na₂SO₄ + BaCl₂ → BaSO₄↓ + 2NaCl (BaSO₄ is the white precipitate.)
1 MarkWhy is respiration considered an exothermic reaction?›
Because during respiration, glucose reacts with oxygen to produce carbon dioxide, water, and energy (heat) is released: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy.
❓ Short Answer Questions (2–3 Marks)
2 MarksExplain with examples: (a) Combination reaction (b) Decomposition reaction›
(a) Combination: Two or more substances combine to form a single product. Example: CaO + H₂O → Ca(OH)₂ (exothermic — releases heat).
(b) Decomposition: A single compound breaks into two or more simpler substances. Example: 2H₂O → 2H₂ + O₂ (electrolysis of water).
(b) Decomposition: A single compound breaks into two or more simpler substances. Example: 2H₂O → 2H₂ + O₂ (electrolysis of water).
3 MarksWhat is a redox reaction? Identify oxidising and reducing agents in: Fe₂O₃ + 2Al → Al₂O₃ + 2Fe›
A redox reaction involves simultaneous oxidation and reduction.
In Fe₂O₃ + 2Al → Al₂O₃ + 2Fe:
• Al is oxidised (gains oxygen) → Al is the REDUCING AGENT.
• Fe₂O₃ is reduced (loses oxygen) → Fe₂O₃ is the OXIDISING AGENT.
In Fe₂O₃ + 2Al → Al₂O₃ + 2Fe:
• Al is oxidised (gains oxygen) → Al is the REDUCING AGENT.
• Fe₂O₃ is reduced (loses oxygen) → Fe₂O₃ is the OXIDISING AGENT.
2 MarksWhy is preventing rancidity important? Mention two methods.›
Rancidity makes food smell and taste bad, and can be harmful to health.
Prevention methods:
1. Storing food in air-tight containers — reduces contact with oxygen.
2. Refrigeration — low temperature slows oxidation.
3. Adding antioxidants (BHA/BHT).
4. Flushing with inert gas (N₂) before packaging.
Prevention methods:
1. Storing food in air-tight containers — reduces contact with oxygen.
2. Refrigeration — low temperature slows oxidation.
3. Adding antioxidants (BHA/BHT).
4. Flushing with inert gas (N₂) before packaging.
❓ Long Answer Question (5 Marks)
5 Marks(a) What is corrosion? (b) Conditions for rusting (c) Two prevention methods (d) Balance: Fe + O₂ + H₂O → Fe₂O₃·H₂O›
(a) Corrosion: The slow deterioration of metals due to chemical reactions with air, moisture, or chemicals. Example: rusting of iron, tarnishing of silver.
(b) Rusting requires: (i) Presence of oxygen, (ii) Presence of moisture (water).
(c) Prevention methods:
• Painting/oiling/greasing — forms a protective layer.
• Galvanisation — coating iron with zinc.
• Alloying — making steel/stainless steel.
• Electroplating with chromium/nickel.
(d) Balanced equation: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O
(b) Rusting requires: (i) Presence of oxygen, (ii) Presence of moisture (water).
(c) Prevention methods:
• Painting/oiling/greasing — forms a protective layer.
• Galvanisation — coating iron with zinc.
• Alloying — making steel/stainless steel.
• Electroplating with chromium/nickel.
(d) Balanced equation: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O
📊 Case Study: Displacement Reaction in Real Life
A student placed an iron nail in a blue solution of copper sulphate (CuSO₄). After 20 minutes, she observed that the blue colour of the solution faded and a reddish-brown deposit appeared on the iron nail.
1 Mark(i) Name the type of reaction taking place.›
It is a displacement (single displacement) reaction.
1 Mark(ii) Write the balanced chemical equation.›
Fe + CuSO₄ → FeSO₄ + Cu2 Marks(iii) Why did the blue colour fade?›
The blue colour is due to Cu²⁺ ions in CuSO₄. Iron displaces copper, so Cu²⁺ ions are removed and the solution turns light green due to FeSO₄ formation.
💡 Assertion-Reason Questions
1 MarkA: Magnesium ribbon burns with a dazzling white light. R: Magnesium reacts with oxygen to form MgO, releasing large energy.›
Answer: (A) — Both A and R are true, and R correctly explains A. The reaction 2Mg + O₂ → 2MgO is highly exothermic, producing intense white light.
1 MarkA: Decomposition reactions are endothermic. R: Energy is required to break the bonds in the reactants.›
Answer: (A) — Both A and R are true, and R correctly explains A. Breaking chemical bonds requires energy input, making most decomposition reactions endothermic.
🧠 Memory Tricks
OIL RIG → Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons)
Types of reactions → 'C D D D' = Combination, Decomposition, Displacement, Double Displacement
Reactivity series (top 5): 'Khalid, Caught, No, Mango, Alu' → K, Ca, Na, Mg, Al
⚗️ Chapter 2: Acids, Bases and Salts
pH Scale · Neutralisation · Salts · Chlor-alkali Process · Bleaching Powder
📖 Key Definitions
| Term | Definition / Property |
|---|---|
| Acid | A substance that produces H⁺ (H₃O⁺) ions in aqueous solution. Tastes sour, turns blue litmus red. |
| Base | A substance that produces OH⁻ ions in aqueous solution. Tastes bitter, turns red litmus blue. |
| Alkali | A base that is soluble in water. Example: NaOH, KOH. |
| Neutralisation | Reaction between an acid and a base to form salt and water: Acid + Base → Salt + Water. |
| pH Scale | A scale (0–14) measuring H⁺ ion concentration. pH < 7 = acidic; pH = 7 = neutral; pH > 7 = basic. |
| Indicator | Substance that changes colour in acidic/basic solutions. Example: litmus, phenolphthalein, methyl orange. |
| Bleaching Powder | Ca(OCl)Cl — used as disinfectant and bleaching agent. |
| Washing Soda | Na₂CO₃·10H₂O — used in cleaning and softening of water. |
| Baking Soda | NaHCO₃ — used in baking powder, antacids. |
📊 pH Values of Common Substances
| Substance | pH Value |
|---|---|
| Gastric juice (stomach acid) | 1.0 – 2.0 |
| Lemon juice | 2.2 – 2.4 |
| Vinegar (acetic acid) | 2.9 – 3.3 |
| Black coffee | 5.0 |
| Pure water | 7.0 (neutral) |
| Blood | 7.35 – 7.45 |
| Baking soda solution | 8.5 |
| Milk of magnesia | 10.5 |
| Bleach (NaOH solution) | 13.5 |
⚗️ Important Chemical Reactions
Key Reactions — Chapter 2
- Acid + Metal: H₂SO₄ + Zn → ZnSO₄ + H₂↑
- Acid + Metal Oxide: H₂SO₄ + CuO → CuSO₄ + H₂O
- Acid + Metal Carbonate: 2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂↑
- Acid + Metal Bicarbonate: HCl + NaHCO₃ → NaCl + H₂O + CO₂↑
- Neutralisation: NaOH + HCl → NaCl + H₂O
- Chlor-alkali process: 2NaCl + 2H₂O → 2NaOH + Cl₂ + H₂
- Bleaching powder: Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O
- Washing soda: Na₂CO₃ + 10H₂O → Na₂CO₃·10H₂O
❓ Very Short Answer Questions (1 Mark)
1 MarkWhat is the pH of a neutral solution?›
The pH of a neutral solution is exactly 7.
1 MarkName the acid present in: (a) vinegar (b) ant's sting (c) tomato›
(a) Acetic acid (CH₃COOH) (b) Formic acid / methanoic acid (HCOOH) (c) Oxalic acid
1 MarkWhat is a universal indicator?›
A universal indicator is a mixture of several indicators that shows different colours for different pH values, allowing precise pH measurement across the full pH scale (0–14).
❓ Short & Long Answer Questions
2 MarksHow does H⁺ concentration change when an acid is diluted? Effect on pH?›
When an acid is diluted, more water is added, which decreases the concentration of H⁺ ions. As H⁺ concentration decreases, the pH value increases (moves closer to 7). Dilution makes the acid weaker but never truly neutral.
3 MarksWhat is the chlor-alkali process? Name three products and one use each.›
Chlor-alkali process: Electrolysis of brine (NaCl solution):
Three products:
1. Sodium hydroxide (NaOH) — making soap and paper.
2. Chlorine (Cl₂) — PVC, disinfecting water.
3. Hydrogen (H₂) — fuel and making HCl.
2NaCl + 2H₂O → 2NaOH + Cl₂ + H₂Three products:
1. Sodium hydroxide (NaOH) — making soap and paper.
2. Chlorine (Cl₂) — PVC, disinfecting water.
3. Hydrogen (H₂) — fuel and making HCl.
5 Marks(a) What is a salt? (b) Preparation of NaCl and Na₂SO₄ (c) Uses of bleaching powder and washing soda›
(a) Salt: Ionic compound formed by neutralisation of an acid with a base.
(b)(i) NaCl: HCl + NaOH → NaCl + H₂O
(b)(ii) Na₂SO₄: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
(c) Bleaching powder uses:
• Bleaching cotton/linen in textile industry.
• Disinfecting drinking water.
• Used as oxidising agent in chemical industry.
Washing soda uses:
• Softening hard water (precipitating Ca²⁺ and Mg²⁺).
• Cleaning agent in households.
• Manufacture of glass and borax.
(b)(i) NaCl: HCl + NaOH → NaCl + H₂O
(b)(ii) Na₂SO₄: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
(c) Bleaching powder uses:
• Bleaching cotton/linen in textile industry.
• Disinfecting drinking water.
• Used as oxidising agent in chemical industry.
Washing soda uses:
• Softening hard water (precipitating Ca²⁺ and Mg²⁺).
• Cleaning agent in households.
• Manufacture of glass and borax.
🌱 Chapter 6: Life Processes
Nutrition · Photosynthesis · Respiration · Circulation · Excretion
📖 Key Concepts
| Process | Definition |
|---|---|
| Nutrition | The process of obtaining food and converting it into energy and organic compounds needed by the organism. |
| Autotrophic Nutrition | Organisms synthesise their own food from inorganic sources (e.g., photosynthesis in plants). |
| Heterotrophic Nutrition | Organisms depend on other organisms for food (e.g., animals, fungi). |
| Photosynthesis | Process by which green plants use sunlight, CO₂, and water to make glucose and oxygen. |
| Respiration | Process of breaking down glucose to release energy. Can be aerobic or anaerobic. |
| Transpiration | Loss of water vapour through stomata of leaves. |
| Translocation | Transport of food (sucrose) through phloem to various parts of the plant. |
| Excretion | Removal of metabolic waste products from the body. |
| Dialysis | Artificial process that mimics kidney function to filter blood. |
🌿 Photosynthesis — In Detail
Photosynthesis
- Overall: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (sunlight + chlorophyll)
- Stage 1 — LIGHT REACTIONS (thylakoid): Photolysis of water → ATP, NADPH, O₂
- Stage 2 — DARK REACTIONS / Calvin Cycle (stroma): CO₂ fixed → glucose
- Requirements: Chlorophyll · Sunlight · CO₂ · Water
- End Products: Glucose (stored as starch) + Oxygen
🫁 Aerobic vs Anaerobic Respiration
| Feature | Aerobic | Anaerobic |
|---|---|---|
| Oxygen required? | YES | NO |
| Site | Mitochondria | Cytoplasm |
| End products | CO₂ + H₂O + Energy | Lactic acid / Ethanol + CO₂ + less Energy |
| Energy yield | 38 ATP (high) | 2 ATP (low) |
| Example organisms | All higher organisms | Yeast, some bacteria |
| Occurs in humans? | Normally yes | During heavy exercise (muscles) |
❓ Short Answer Questions
1 MarkName the process by which plants lose water vapour.›
Transpiration
1 MarkWhat is the role of HCl in the stomach?›
HCl: (1) Creates an acidic medium for pepsin (enzyme) to work. (2) Kills harmful bacteria in food. (3) Denatures (unfolds) proteins to aid digestion.
1 MarkWhere does digestion of starch begin in humans?›
In the mouth — salivary amylase (ptyalin) in saliva begins starch digestion.
3 MarksDescribe the transport of water and minerals in plants.›
Water and minerals are transported from roots to leaves through xylem vessels.
Process:
1. Root hair cells absorb water and minerals by osmosis.
2. Water moves from root hair → cortex → xylem by osmosis.
3. Root pressure and transpiration pull (cohesion-tension) drive water upward.
4. Water reaches leaves for photosynthesis.
Process:
1. Root hair cells absorb water and minerals by osmosis.
2. Water moves from root hair → cortex → xylem by osmosis.
3. Root pressure and transpiration pull (cohesion-tension) drive water upward.
4. Water reaches leaves for photosynthesis.
3 MarksWhat is the role of nephrons in the human excretory system?›
Nephron is the structural and functional unit of the kidney. It filters blood through three processes:
1. Ultrafiltration: Blood is filtered in Bowman's capsule — large molecules (proteins, RBCs) are retained.
2. Selective Reabsorption: Useful substances like glucose, amino acids, and water are reabsorbed in the tubules.
3. Secretion: Excess ions and toxins are secreted into the filtrate.
The remaining fluid becomes urine, which flows to the ureter.
1. Ultrafiltration: Blood is filtered in Bowman's capsule — large molecules (proteins, RBCs) are retained.
2. Selective Reabsorption: Useful substances like glucose, amino acids, and water are reabsorbed in the tubules.
3. Secretion: Excess ions and toxins are secreted into the filtrate.
The remaining fluid becomes urine, which flows to the ureter.
📊 Case Study — Double Circulation
The human heart pumps blood through two separate circuits simultaneously. Oxygenated blood from the lungs reaches the left atrium → left ventricle → pumped to the body. Deoxygenated blood returns to the right atrium → right ventricle → sent to the lungs.
2 Marks(i) Why is double circulation important?›
It prevents mixing of oxygenated and deoxygenated blood, ensuring efficient oxygen supply to all body tissues. This is especially important for warm-blooded animals with high energy needs.
2 Marks(ii) What are the two circuits in double circulation?›
1. Pulmonary circulation: Right heart → Lungs → Left heart (for oxygenation).
2. Systemic circulation: Left heart → Body tissues → Right heart (to supply oxygen and collect CO₂).
2. Systemic circulation: Left heart → Body tissues → Right heart (to supply oxygen and collect CO₂).
🧬 Chapter 9: Heredity
Mendel's Laws · Monohybrid Cross · Sex Determination · Genetics Terminology
📖 Key Terms
| Term | Meaning |
|---|---|
| Heredity | Transmission of characters from parents to offspring. |
| Gene | Unit of heredity; a segment of DNA that codes for a specific protein/trait. |
| Allele | Alternative forms of a gene (dominant or recessive). |
| Dominant Allele | Allele whose effect is expressed in the phenotype even in heterozygous state (capital letter). |
| Recessive Allele | Allele whose effect is expressed only in homozygous state (small letter). |
| Genotype | Genetic constitution of an organism (e.g., Tt, TT, tt). |
| Phenotype | Observable physical characteristic (e.g., tall, short). |
| Homozygous | Both alleles for a trait are identical (TT or tt). |
| Heterozygous | Two different alleles for a trait (Tt). |
| F₁ Generation | First filial generation — offspring of cross between parents. |
| F₂ Generation | Second filial generation — offspring of F₁ × F₁. |
🌿 Mendel's Laws of Inheritance
LAW 1 — Law of Dominance
When two homozygous parents (TT × tt) are crossed, the F₁ offspring all show the dominant character.
LAW 2 — Law of Segregation (Law of Purity of Gametes)
During gamete formation, the two alleles of a gene separate so each gamete receives only one allele.
F₂ ratio for monohybrid cross: 3 dominant : 1 recessive
LAW 3 — Law of Independent Assortment
Genes for different traits assort independently during gamete formation.
F₂ ratio for dihybrid cross: 9 : 3 : 3 : 1
Mendel chose garden peas (Pisum sativum) with 7 pairs of contrasting traits.
❓ Short Answer Questions
3 MarksShow the F₁ and F₂ results of a monohybrid cross between tall (TT) and dwarf (tt) pea plants.›
P: TT × tt → F₁: All Tt (tall, heterozygous)
F₁ × F₁: Tt × Tt → F₂: TT : Tt : tt = 1:2:1
Phenotype ratio in F₂: 3 Tall : 1 Dwarf
This demonstrates Mendel's Law of Segregation — the T and t alleles separate during gamete formation.
F₁ × F₁: Tt × Tt → F₂: TT : Tt : tt = 1:2:1
Phenotype ratio in F₂: 3 Tall : 1 Dwarf
This demonstrates Mendel's Law of Segregation — the T and t alleles separate during gamete formation.
3 MarksHow is the sex of a child determined in humans?›
Humans have 23 pairs of chromosomes; the 23rd pair are sex chromosomes.
• Males: XY • Females: XX
During gamete formation:
• Females produce only X-carrying eggs.
• Males produce X or Y sperm.
• If X sperm fertilises egg → XX = Girl
• If Y sperm fertilises egg → XY = Boy
Therefore, it is the FATHER's sperm that determines the sex of the child.
• Males: XY • Females: XX
During gamete formation:
• Females produce only X-carrying eggs.
• Males produce X or Y sperm.
• If X sperm fertilises egg → XX = Girl
• If Y sperm fertilises egg → XY = Boy
Therefore, it is the FATHER's sperm that determines the sex of the child.
🔭 Chapter 10: Light — Reflection and Refraction
Mirror Formula · Lens Formula · Snell's Law · Image Formation · Power of Lens
📐 Key Formulae
Important Formulae — Mirrors & Lenses
- MIRROR FORMULA: 1/f = 1/v + 1/u
- MAGNIFICATION (Mirror): m = -v/u = h'/h
- SNELL'S LAW: n₁ sin θ₁ = n₂ sin θ₂
- REFRACTIVE INDEX: n = c/v (speed in vacuum / speed in medium)
- LENS FORMULA: 1/f = 1/v - 1/u
- MAGNIFICATION (Lens): m = v/u = h'/h
- POWER OF LENS: P = 1/f (in metres) ; Unit = Dioptre (D)
- Sign Convention: Incident ray direction = positive; opposite = negative
🪞 Concave Mirror — Image Positions
| Object at | Image at | Nature | Size |
|---|---|---|---|
| Infinity | At F | Real, inverted | Point |
| Beyond C | Between F & C | Real, inverted | Diminished |
| At C | At C | Real, inverted | Same size |
| Between C & F | Beyond C | Real, inverted | Enlarged |
| At F | At infinity | Real, inverted | Highly enlarged |
| Between F & P | Behind mirror | Virtual, erect | Enlarged |
🔍 Convex Lens — Image Positions
| Object at | Image at | Nature | Size |
|---|---|---|---|
| Infinity | At F₂ | Real, inverted | Point |
| Beyond 2F₁ | Between F₂ & 2F₂ | Real, inverted | Diminished |
| At 2F₁ | At 2F₂ | Real, inverted | Same size |
| Between F₁ & 2F₁ | Beyond 2F₂ | Real, inverted | Enlarged |
| At F₁ | At infinity | Real, inverted | Highly enlarged |
| Between O & F₁ | Same side | Virtual, erect | Enlarged |
❓ Questions on Light
1 MarkWhat is the power of a concave lens of focal length 25 cm?›
P = 1/f = 1/(−0.25 m) = −4 D (negative sign for concave/diverging lens)
1 MarkDefine refractive index.›
Refractive index (n) of a medium is the ratio of the speed of light in vacuum (c) to the speed of light in that medium (v): n = c/v. It indicates how much light bends when entering the medium.
3 MarksA convex lens has focal length 10 cm. Object placed 15 cm from lens. Find: (a) image distance (b) magnification.›
(a) Using lens formula: 1/f = 1/v − 1/u
u = −15 cm, f = +10 cm
1/10 = 1/v − 1/(−15) → 1/v = 1/10 − 1/15 = (3−2)/30 = 1/30
∴ v = +30 cm (image is real, on opposite side)
(b) Magnification m = v/u = 30/(−15) = −2 (real, inverted, magnified 2×)
u = −15 cm, f = +10 cm
1/10 = 1/v − 1/(−15) → 1/v = 1/10 − 1/15 = (3−2)/30 = 1/30
∴ v = +30 cm (image is real, on opposite side)
(b) Magnification m = v/u = 30/(−15) = −2 (real, inverted, magnified 2×)
3 MarksState the laws of refraction (Snell's law). What is total internal reflection?›
Laws of Refraction:
1. The incident ray, refracted ray, and normal all lie in the same plane.
2. Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
Total Internal Reflection: When light travels from a denser to rarer medium and the angle of incidence exceeds the critical angle, ALL light is reflected back into the denser medium. This is the principle of optical fibres.
1. The incident ray, refracted ray, and normal all lie in the same plane.
2. Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
Total Internal Reflection: When light travels from a denser to rarer medium and the angle of incidence exceeds the critical angle, ALL light is reflected back into the denser medium. This is the principle of optical fibres.
⚡ Chapter 12: Electricity
Ohm's Law · Resistance · Series & Parallel Circuits · Power · Heating Effect
📖 Key Definitions & Formulae
| Term / Formula | Explanation |
|---|---|
| Electric Charge (Q) | Q = n × e (n = number of electrons, e = 1.6 × 10⁻¹⁹ C) |
| Electric Current (I) | I = Q/t ; Unit: Ampere (A) |
| Potential Difference (V) | V = W/Q ; Unit: Volt (V) |
| Ohm's Law | V = I × R (V: voltage, I: current, R: resistance) |
| Resistance (R) | R = ρl/A (ρ: resistivity, l: length, A: cross-section area) |
| Resistors in Series | Rₛ = R₁ + R₂ + R₃ |
| Resistors in Parallel | 1/Rₚ = 1/R₁ + 1/R₂ + 1/R₃ |
| Electric Power (P) | P = VI = I²R = V²/R ; Unit: Watt (W) |
| Electric Energy (E) | E = P × t = VIt ; Unit: Joule (J) or kWh |
| 1 kWh | 1 kWh = 3.6 × 10⁶ J |
| Heating Effect (Joule's Law) | H = I²Rt (heat produced in a resistor) |
🔌 Series vs Parallel Circuits
SERIES CIRCUIT
- Same current through all components.
- Total voltage = sum of individual voltages.
- R_total = R₁ + R₂ + ...
- If one fails, circuit breaks.
PARALLEL CIRCUIT
- Same voltage across all components.
- Total current = sum of individual currents.
- Total resistance < smallest individual R.
- If one fails, others continue. Used in homes!
❓ Questions on Electricity
1 MarkState Ohm's Law.›
The electric current (I) flowing through a conductor is directly proportional to the potential difference (V) across its ends, provided temperature and other physical conditions remain constant. V = IR
1 MarkThree resistors of 2Ω, 3Ω, and 6Ω connected in parallel. Find total resistance.›
1/R = 1/2 + 1/3 + 1/6 = 3/6 + 2/6 + 1/6 = 6/6 = 1 → R = 1Ω
3 MarksAn electric iron (resistance 20Ω) draws 5A current. Find: (a) voltage (b) power (c) energy in 2 hours.›
(a) V = IR = 5 × 20 = 100 V
(b) P = I²R = 25 × 20 = 500 W
(c) E = P × t = 500 W × 2 h = 1000 Wh = 1 kWh (Cost at ₹6/unit = ₹6)
(b) P = I²R = 25 × 20 = 500 W
(c) E = P × t = 500 W × 2 h = 1000 Wh = 1 kWh (Cost at ₹6/unit = ₹6)
3 MarksWhy are resistors connected in parallel preferred for household appliances?›
In parallel:
1. Each appliance gets the same full voltage (220V).
2. Each can be independently switched on/off.
3. Failure of one appliance does not affect others.
4. Total resistance is low, so total current is sufficient.
5. High-power (AC, heaters) and low-power (bulbs) appliances can coexist safely.
1. Each appliance gets the same full voltage (220V).
2. Each can be independently switched on/off.
3. Failure of one appliance does not affect others.
4. Total resistance is low, so total current is sufficient.
5. High-power (AC, heaters) and low-power (bulbs) appliances can coexist safely.
Quick Revision — Chapter Summaries
Key concepts and formulae at a glance
| Chapter | Key Concept 1 | Key Concept 2 | Key Formula/Fact |
|---|---|---|---|
| 1. Chem Reactions | Types: Combination, Decomposition, Displacement, Double Displacement, Redox | Exothermic: releases heat; Endothermic: absorbs heat | OIL RIG — Oxidation Is Loss; Reduction Is Gain |
| 2. Acids, Bases, Salts | Acid: H⁺ ions; Base: OH⁻ ions; pH < 7 = acid, > 7 = base | Neutralisation: Acid + Base → Salt + Water | Chlor-alkali: 2NaCl+2H₂O → 2NaOH+Cl₂+H₂ |
| 3. Metals & Non-metals | Metals: malleable, ductile, good conductors | Reactivity series determines displacement | Corrosion = slow oxidation of metals |
| 4. Carbon Compounds | Carbon forms covalent bonds; homologous series | Soaps are sodium salts of fatty acids | CnH₂n+₂ = alkane; CnH₂n = alkene |
| 6. Life Processes | Photosynthesis: 6CO₂+6H₂O → C₆H₁₂O₆+6O₂ | Aerobic: 38 ATP; Anaerobic: 2 ATP | Nephron = structural & functional unit of kidney |
| 9. Heredity | Mendel's 3 laws: Dominance, Segregation, Independent Assortment | F₂ monohybrid: 3:1 phenotype ratio | Sex: Father's sperm determines (X → girl, Y → boy) |
| 10. Light | Mirror formula: 1/f = 1/v + 1/u | Lens formula: 1/f = 1/v - 1/u | Power = 1/f(m) in Dioptre (D) |
| 12. Electricity | Ohm's Law: V = IR | Parallel circuit: preferred for household wiring | Power: P = VI = I²R = V²/R; H = I²Rt |
Model Question Papers
Three full-length papers for complete Board Exam practice
01
📄 Model Question Paper — 1
Subject: Science | Class X | Time: 3 Hours | Maximum Marks: 80
Section A — MCQ & Assertion-Reason (1 Mark Each)
Q1. Which of the following is an exothermic reaction?
(A) Decomposition of CaCO₃(B) Dissolution of NH₄Cl(C) Burning of coal(D) Electrolysis of water
✅ Answer: (C) Burning of coal — releases heat energy to surroundings.
Q2. Which of the following represents a decomposition reaction?
(A) NaOH + HCl → NaCl + H₂O(B) 2H₂O → 2H₂ + O₂(C) Fe + S → FeS(D) AgNO₃ + NaCl → AgCl + NaNO₃
✅ Answer: (B) 2H₂O → 2H₂ + O₂
Q3. pH of a solution is 3. Which indicator would turn RED?
(A) Phenolphthalein(B) Methyl orange(C) Litmus(D) Both B and C
✅ Answer: (D) Both B and C — both turn red/pink in acidic solution.
Q4. Which part of the nephron is responsible for filtration of blood?
(A) Loop of Henle(B) Collecting duct(C) Bowman's capsule(D) Proximal tubule
✅ Answer: (C) Bowman's capsule
Q5. The power of a convex lens is +4 D. Its focal length is:
(A) 4 m(B) 25 cm(C) 0.4 m(D) 40 cm
✅ Answer: (B) 25 cm [f = 1/P = 1/4 = 0.25 m = 25 cm]
Q6. What is the SI unit of electric resistance?
(A) Volt(B) Ampere(C) Ohm(D) Watt
✅ Answer: (C) Ohm (Ω)
Section B — Short Answer (2 Marks Each)
2 MarksQ21. What is corrosion? Write two methods to prevent it.›
Corrosion is the slow deterioration of metals due to chemical reactions with oxygen, moisture, or other chemicals.
Prevention: (1) Galvanisation — coating iron with zinc. (2) Painting or oiling to prevent exposure.
Prevention: (1) Galvanisation — coating iron with zinc. (2) Painting or oiling to prevent exposure.
2 MarksQ22. Name the hormone produced by the pancreas. Write its function.›
(1) Insulin — lowers blood glucose by promoting uptake of glucose by cells.
(2) Glucagon — raises blood glucose level by promoting glycogen breakdown.
(2) Glucagon — raises blood glucose level by promoting glycogen breakdown.
2 MarksQ23. A piece of iron is dipped in copper sulphate solution. What do you observe and why?›
Observation: The blue colour of CuSO₄ fades and a reddish-brown deposit of copper forms on the iron.
Reason: Iron displaces copper since iron is more reactive. Fe + CuSO₄ → FeSO₄ + Cu
Reason: Iron displaces copper since iron is more reactive. Fe + CuSO₄ → FeSO₄ + Cu
Section C — Short Answer (3 Marks Each)
3 MarksQ27. Explain the structure and function of the human heart.›
The human heart is a muscular organ with four chambers: right atrium, right ventricle, left atrium, left ventricle. Valves (tricuspid, bicuspid, semilunar) prevent backflow.
Functioning: Deoxygenated blood enters right atrium → right ventricle → pulmonary artery → lungs → (oxygenated) → left atrium → left ventricle → aorta → body. This double circulation ensures efficient oxygen delivery.
Functioning: Deoxygenated blood enters right atrium → right ventricle → pulmonary artery → lungs → (oxygenated) → left atrium → left ventricle → aorta → body. This double circulation ensures efficient oxygen delivery.
3 MarksQ28. State the factors affecting resistance of a conductor.›
Resistance (R) depends on:
1. Length (l): R ∝ l — longer wire has more resistance.
2. Cross-sectional area (A): R ∝ 1/A — thicker wire has less resistance.
3. Material (ρ): R = ρl/A — depends on resistivity of the material.
4. Temperature: Resistance of metals increases with temperature.
1. Length (l): R ∝ l — longer wire has more resistance.
2. Cross-sectional area (A): R ∝ 1/A — thicker wire has less resistance.
3. Material (ρ): R = ρl/A — depends on resistivity of the material.
4. Temperature: Resistance of metals increases with temperature.
3 MarksQ29. What is a food chain? Give an example with 4 trophic levels. What is the 10% law?›
Food chain: A sequence showing feeding relationships and energy flow between organisms.
Example: Grass → Grasshopper → Frog → Snake → Hawk
10% Law (Lindeman): Only 10% of energy from one trophic level is transferred to the next; 90% is lost as heat, respiration, and waste. This limits trophic levels to 3–4 in most ecosystems.
Example: Grass → Grasshopper → Frog → Snake → Hawk
10% Law (Lindeman): Only 10% of energy from one trophic level is transferred to the next; 90% is lost as heat, respiration, and waste. This limits trophic levels to 3–4 in most ecosystems.
Section D — Long Answer (5 Marks Each)
5 MarksQ34. (a) Define refraction. (b) State Snell's law. (c) Ray enters from air into glass (n=1.5) at 30°. Find angle of refraction.›
(a) Refraction: The bending of light as it passes from one medium to another due to change in speed.
(b) Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
(c) n₁ = 1, θ₁ = 30°, n₂ = 1.5
sin θ₂ = (1/1.5) × sin 30° = (1/1.5) × 0.5 = 0.333
∴ θ₂ = sin⁻¹(0.333) ≈ 19.5°
Uses of concave mirror: (1) Shaving/make-up mirrors (magnified image). (2) Headlights of vehicles (parallel beam of light).
(b) Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
(c) n₁ = 1, θ₁ = 30°, n₂ = 1.5
sin θ₂ = (1/1.5) × sin 30° = (1/1.5) × 0.5 = 0.333
∴ θ₂ = sin⁻¹(0.333) ≈ 19.5°
Uses of concave mirror: (1) Shaving/make-up mirrors (magnified image). (2) Headlights of vehicles (parallel beam of light).
Section E — Case Study (4 Marks Each)
Q37. Riya's grandmother has difficulty reading newspapers close-up. The doctor found she has a condition where the near point has shifted beyond 25 cm.
1 Mark(i) Name the defect of vision.›
Hypermetropia (far-sightedness) / Presbyopia for age-related. The near point shifts beyond 25 cm, making close objects blurry.
1 Mark(ii) What is the cause of hypermetropia?›
Hypermetropia is caused by: (1) The eyeball being too short, OR (2) The focal length of eye lens being too large. Light focuses behind the retina.
2 Marks(iii) Which type of lens corrects this defect? Explain how.›
Convex (converging) lens corrects hypermetropia. A convex lens converges the diverging rays from a nearby object before entering the eye, allowing the image to focus correctly on the retina.
02
📄 Model Question Paper — 2
Subject: Science | Class X | Time: 3 Hours | Maximum Marks: 80
Section A — MCQ (1 Mark Each)
Q1. Which gas is produced when zinc reacts with dilute sulphuric acid?
(A) O₂(B) SO₂(C) H₂(D) CO₂
✅ Answer: (C) H₂ [Zn + H₂SO₄ → ZnSO₄ + H₂↑]
Q2. The functional unit of kidney is called:
(A) Neuron(B) Nephron(C) Nidus(D) Nodule
✅ Answer: (B) Nephron
Q3. ASSERTION: Electric resistance increases with temperature in metals. REASON: Increased temperature causes more atomic vibrations, obstructing electron flow.
(A) Both A and R true, R is correct explanation(B) Both true, R not correct explanation(C) A true, R false(D) A false, R true
✅ Answer: (A) — Both are true and R correctly explains A.
Q4. A carbon compound with formula C₃H₆ belongs to which homologous series?
(A) Alkane(B) Alkene(C) Alkyne(D) Alcohol
✅ Answer: (B) Alkene [General formula CnH₂n; for n=3: C₃H₆]
Q5. The colour of litmus in a neutral solution is:
(A) Red(B) Blue(C) Purple/Violet(D) Colourless
✅ Answer: (C) Purple/Violet
Section B & C — Selected Questions
2 MarksQ21. Difference between autotrophic and heterotrophic nutrition.›
Autotrophic: Organisms prepare their own food from inorganic substances. Example: Green plants (photosynthesis).
Heterotrophic: Organisms depend on other organisms for food. Example: Humans, animals, fungi.
Heterotrophic: Organisms depend on other organisms for food. Example: Humans, animals, fungi.
2 MarksQ22. Two resistors 4Ω and 6Ω in (a) series (b) parallel. Find effective resistance.›
(a) Series: Rₛ = 4 + 6 = 10Ω
(b) Parallel: 1/Rₚ = 1/4 + 1/6 = 3/12 + 2/12 = 5/12 → Rₚ = 2.4Ω
(b) Parallel: 1/Rₚ = 1/4 + 1/6 = 3/12 + 2/12 = 5/12 → Rₚ = 2.4Ω
3 MarksQ27. Explain Mendel's monohybrid cross experiment. What ratio in F₂?›
Mendel crossed pure tall (TT) plants with pure dwarf (tt) plants.
F₁: All plants were tall (Tt) — dominance of T over t.
F₁ × F₁: Tt × Tt → F₂: TT : 2Tt : tt = 1:2:1 (genotype).
Phenotype ratio = 3 Tall : 1 Dwarf
This demonstrated the Law of Segregation — alleles separate during gamete formation and recombine randomly.
F₁: All plants were tall (Tt) — dominance of T over t.
F₁ × F₁: Tt × Tt → F₂: TT : 2Tt : tt = 1:2:1 (genotype).
Phenotype ratio = 3 Tall : 1 Dwarf
This demonstrated the Law of Segregation — alleles separate during gamete formation and recombine randomly.
3 MarksQ28. Difference between soaps and detergents. Why do soaps not work in hard water?›
Soaps: Sodium/potassium salts of long-chain fatty acids. Made from fats/vegetable oils. Biodegradable. Do NOT work in hard water.
Detergents: Ammonium or sulphonate salts. Synthetic. Work in hard water.
Soaps in hard water: Ca²⁺ and Mg²⁺ ions react with soap to form insoluble scum (calcium/magnesium stearate), wasting soap and leaving residue.
Detergents: Ammonium or sulphonate salts. Synthetic. Work in hard water.
Soaps in hard water: Ca²⁺ and Mg²⁺ ions react with soap to form insoluble scum (calcium/magnesium stearate), wasting soap and leaving residue.
5 MarksQ34. Describe the structure of the human brain and the function of each part.›
(1) FOREBRAIN (Cerebrum): Largest part. Controls intelligence, memory, reasoning, voluntary actions, sensory perception, language, and emotions.
(2) MIDBRAIN: Connects forebrain and hindbrain. Controls visual and auditory reflexes; regulates eye movement.
(3) HINDBRAIN:
• Cerebellum: Controls balance, coordination, and precise voluntary movements.
• Pons: Regulates breathing and acts as relay station.
• Medulla Oblongata: Controls involuntary functions — heartbeat, breathing, blood pressure, swallowing.
Meninges — three membranes protect the brain. CSF — cushions the brain from shocks.
(2) MIDBRAIN: Connects forebrain and hindbrain. Controls visual and auditory reflexes; regulates eye movement.
(3) HINDBRAIN:
• Cerebellum: Controls balance, coordination, and precise voluntary movements.
• Pons: Regulates breathing and acts as relay station.
• Medulla Oblongata: Controls involuntary functions — heartbeat, breathing, blood pressure, swallowing.
Meninges — three membranes protect the brain. CSF — cushions the brain from shocks.
03
📄 Model Question Paper — 3
Subject: Science | Class X | Time: 3 Hours | Maximum Marks: 80 | 🔥 Ideal for final revision
Section A — MCQ (1 Mark Each)
Q1. The type of nutrition seen in Amoeba is:
(A) Autotrophic(B) Holozoic(C) Saprotrophic(D) Parasitic
✅ Answer: (B) Holozoic — Amoeba engulfs food particles (pseudopodia) and digests internally.
Q2. The reactivity series helps to predict:
(A) Colour of metals(B) Melting point(C) Whether a metal can displace another from salt solution(D) Atomic mass
✅ Answer: (C) A more reactive metal displaces a less reactive metal from its salt solution.
Q3. An object is placed at the centre of curvature of a concave mirror. The image formed is:
(A) Virtual, erect, diminished(B) Real, inverted, same size(C) Real, inverted, enlarged(D) Virtual, erect, enlarged
✅ Answer: (B) Real, inverted, same size — forms at C itself.
Q4. CFCs (chlorofluorocarbons) cause damage to the:
(A) Hydrosphere(B) Lithosphere(C) Ozone layer(D) Biosphere
✅ Answer: (C) Ozone layer — CFCs release chlorine radicals that destroy ozone (O₃).
Q5. The magnification produced by a plane mirror is:
(A) +1(B) −1(C) 0(D) Infinity
✅ Answer: (A) +1 — Image is virtual, erect, and same size as object.
Section B, C, D — Selected Questions
2 MarksQ21. What is electromagnetic induction? Name one device based on it.›
Electromagnetic induction: The process of producing an electric current in a conductor by changing the magnetic flux through it (Faraday's discovery).
Device: Electric Generator (AC/DC) — converts mechanical energy to electrical energy. Also: Transformers, induction coils.
Device: Electric Generator (AC/DC) — converts mechanical energy to electrical energy. Also: Transformers, induction coils.
2 MarksQ22. Why is the sky blue? Why is it red/orange at sunrise and sunset?›
Blue sky: Shorter wavelength blue light is scattered more by air molecules (Rayleigh scattering), so the sky appears blue.
Red/orange sunrise-sunset: Sunlight travels through a much longer path of atmosphere. Blue light gets scattered away, and longer wavelength red and orange light reaches our eyes.
Red/orange sunrise-sunset: Sunlight travels through a much longer path of atmosphere. Blue light gets scattered away, and longer wavelength red and orange light reaches our eyes.
3 MarksQ27. What is ozone? How is the ozone layer being depleted? Write its consequences.›
Ozone (O₃): Triatomic form of oxygen present in the stratosphere (15–35 km). Absorbs harmful UV radiation.
Depletion: CFCs release chlorine radicals that catalytically destroy ozone: Cl + O₃ → ClO + O₂
Consequences: (1) Increased UV radiation reaching Earth. (2) Higher risk of skin cancer, cataracts. (3) Harm to marine ecosystems and phytoplankton. (4) Disruption of food chains.
Depletion: CFCs release chlorine radicals that catalytically destroy ozone: Cl + O₃ → ClO + O₂
Consequences: (1) Increased UV radiation reaching Earth. (2) Higher risk of skin cancer, cataracts. (3) Harm to marine ecosystems and phytoplankton. (4) Disruption of food chains.
5 MarksQ34. (a) What is an electric motor? Explain its working. (b) Principle. (c) Two applications.›
(a) Electric Motor: A device that converts electrical energy into mechanical (rotational) energy.
Working: A rectangular coil (armature) is placed between poles of a permanent magnet. When current flows, it experiences a force (Fleming's left-hand rule) causing rotation. The split-ring commutator reverses current every half rotation, maintaining continuous rotation.
(b) Principle: When a current-carrying conductor is placed in a magnetic field, it experiences a force (F = BIL).
(c) Applications: (1) Electric fans. (2) Washing machines. (3) Electric vehicles.
Working: A rectangular coil (armature) is placed between poles of a permanent magnet. When current flows, it experiences a force (Fleming's left-hand rule) causing rotation. The split-ring commutator reverses current every half rotation, maintaining continuous rotation.
(b) Principle: When a current-carrying conductor is placed in a magnetic field, it experiences a force (F = BIL).
(c) Applications: (1) Electric fans. (2) Washing machines. (3) Electric vehicles.
Section E — Case Study
Q37. Seema's class was studying about the reactivity series. Her teacher said metals higher in the series are more reactive and can displace metals lower in the series from their salt solutions.
1 Mark(i) Arrange in increasing reactivity: Cu, Mg, Fe, Ag›
Cu < Ag < Fe < Mg (Increasing reactivity; Mg is most reactive, Ag is least reactive among these.)
2 Marks(ii) Will iron displace copper from copper sulphate solution? Write equation.›
Yes. Iron is more reactive than copper (Fe > Cu in reactivity series).
Iron dissolves and copper is deposited as reddish-brown solid. The blue colour of CuSO₄ fades.
Fe + CuSO₄ → FeSO₄ + CuIron dissolves and copper is deposited as reddish-brown solid. The blue colour of CuSO₄ fades.
1 Mark(iii) Why is gold found in free state but sodium is not?›
Gold is very low in the reactivity series — it does not react with air, water, or most acids, so it is found free in nature. Sodium is extremely reactive — it reacts vigorously with air and water, so it is always found in combined form (NaCl, Na₂CO₃, etc.).
Important Diagrams — Labeling Practice
CBSE allocates 5–6 marks for diagrams every year. Practice drawing and labeling these at least 3 times.
| # | Diagram | Key Labels to Include |
|---|---|---|
| 1 | Human Excretory System | Kidney, Ureter, Urinary Bladder, Urethra, Renal artery, Renal vein |
| 2 | Nephron (Cross-section) | Bowman's capsule, Glomerulus, PCT, Loop of Henle, DCT, Collecting duct |
| 3 | Human Heart | 4 chambers, Valves (tricuspid, bicuspid, semilunar), Aorta, Pulmonary artery/vein, Vena cava |
| 4 | Neuron | Cell body (soma), Dendrites, Axon, Myelin sheath, Node of Ranvier, Synapse |
| 5 | Human Brain | Cerebrum, Cerebellum, Pons, Medulla oblongata, Spinal cord |
| 6 | Reflex Arc | Receptor, Sensory nerve, Spinal cord, Motor nerve, Effector (muscle) |
| 7 | Concave Mirror Ray Diagram | Pole, Principal axis, Centre of curvature, Focus, Object, Image, Reflected rays |
| 8 | Convex Lens Ray Diagram | Optical centre, F₁, F₂, 2F₁, 2F₂, Object, Image |
| 9 | Human Eye | Cornea, Iris, Pupil, Lens, Retina, Optic nerve, Ciliary muscles, Aqueous/Vitreous humor |
| 10 | Electric Motor | Armature coil, Permanent magnet (N/S poles), Split-ring commutator, Brushes, Battery |
| 11 | Bisection of Flower | Sepal, Petal, Stamen (anther+filament), Pistil (stigma+style+ovary), Ovule |
| 12 | Monohybrid Cross | Parent phenotypes, Gametes, F₁ phenotype, F₂ Punnett square, F₂ ratio |
Use pencil for diagrams, pen for labels. Draw arrow lines for labels — they should never cross. Write the diagram title below. Minimum 4 labels required for full marks. Neat > elaborate — don't shade excessively.
🌟 You've Got This!
You have just completed one of the most comprehensive Science guides for Class 10 CBSE. Walk into that exam hall with confidence!
📖 UNDERSTAND, don't just memorise — Science makes sense when you understand why.
✍️ WRITE daily — practice writing answers, not just reading them.
📐 DRAW diagrams — 5 marks depend on your ability to draw and label correctly.
🔢 SOLVE numericals — at least 10 numericals per chapter before the exam.
😴 REST & REVISE — Sleep 7–8 hours. A fresh mind retains more than a tired one.
"Science is not just a subject — it is a way of thinking. Think. Question. Discover." 🚀🎓
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