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🔥 HBSE Class 10 Science 2026 | 5 Years PYQs + 80% Most Important Questions 💯

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✅ HBSE Class 10 Science 2021

Table of Contents

✳ SECTION – A (PHYSICS)

1. Rear view mirror →

Ans: (B) Convex

2. Sky blue due to →

Ans: (B) Scattering

3. Not a conventional source of energy →

Ans: (B) Solar energy

4. SI unit of electric charge →

Ans: (C) Coulomb

5. Not a natural resource →

Ans: (C) Electricity

6. Image formed in human eye at →

Ans: (A) Retina

7. Gas not released during burning of fossil fuels →

Ans: (D) Oxygen

8. Fuel most used for cooking in India →

Ans: (B) LPG

9. Second R in 5R’s →

Ans: (B) Reuse

10. Total energy in physical/chemical process →

Ans: (C) Remains unchanged

✳ SECTION – B (CHEMISTRY)

11. Acid present in tomato →

Oxalic Acid

12. Why paint iron articles?

To prevent rusting (corrosion) by stopping contact with air and moisture.

13. Liquid non-metal →

Bromine

14. Metal soft & cut with knife →

Sodium

15. Unsaturated compound →

(C) Benzene

16. AgNO₃ + NaBr →

(C) Double displacement reaction

17. Covalent bonds in ethane →

Ethane (C₂H₆) → 7 covalent bonds
Ans: (B) 7

18. Homologous series difference →

(B) CH₂

✳ SECTION – C (BIOLOGY)

19. Kidneys are part of →

(C) Excretion

20. Autotrophic nutrition requires →

(D) All of the above

21. Not a part of female reproductive system →

(C) Vas deferens

22. Cross pollination achieved by →

(D) All of the above

23. Food chain →

(B) Grass, goat and human

24. Non-biodegradable substance →

(D) Plastic

25. Break down complex substances →

(A) Decomposers

26. Control & coordination by →

(C) Nervous system

27. Longest part of alimentary canal →

Small Intestine

28. Sex chromosome in males →

XY

29. Spinal cord protected by →

(B) Vertebral column

30. Mendel studied characters in →

Pea plant

📘 HBSE Class 10 Science 2023

मैं पूरा पेपर Section-wise + Board Answer Format में सॉल्व कर रहा हूँ।

✳ SECTION – A (PHYSICS)

Q1. Least distance of distinct vision →

Ans: (B) 25 cm

Q2. Not a natural resource →

Ans: (C) Electricity

Q3. SI unit of electric current →

Ans: (A) Ampere

Q4. Tehri dam is built on →

Ans: (C) Ganga

Q5. Why do stars twinkle? (2 Marks)

Stars twinkle due to atmospheric refraction.
Light from stars passes through different layers of atmosphere having varying density, causing continuous bending of light rays. This makes stars appear to twinkle.

Q6. Characteristics of good source of energy (2 Marks)

  1. High calorific value

  2. Easily available

  3. Easy to store & transport

  4. Causes less pollution

Q7. Electric charge (2 Marks)

Given:
I = 0.5 A
t = 5 min = 300 s

Formula:
Q = I × t

Q = 0.5 × 300 = 150 C

Q8. Electric Motor (4 Marks)

Definition:
An electric motor is a device that converts electrical energy into mechanical energy.

Principle:
It works on the principle that a current carrying conductor placed in a magnetic field experiences a force. (Fleming’s Left Hand Rule)

Diagram: (Draw labelled diagram showing coil, magnet, battery, split ring)

Q9 (a) Laws of reflection (2 Marks)

  1. Angle of incidence = Angle of reflection

  2. Incident ray, reflected ray and normal lie in same plane

Q9 (b) Convex lens image (2 Marks)

Object between F1 and 2F1:
Image formed →

  • Beyond 2F2

  • Real

  • Inverted

  • Enlarged

(Draw ray diagram)

Q9 (c) Focal length of convex mirror

R = 36 cm
Formula: f = R/2

f = 36/2 = 18 cm

✳ SECTION – B (CHEMISTRY)

Q10. Balanced equation with state symbols

Correct answer → (B)

Q11. Basis of modern periodic table →

Ans: (B) Atomic number

Q12. Chemical name of baking soda →

Ans: (B) Sodium hydrogen carbonate

Q13. Ferrous sulphate crystals (2 Marks)

Colour: Light green

On heating:
Turns white (anhydrous FeSO₄)
Further heating → brown (Fe₂O₃)

Reaction:
2FeSO₄ → Fe₂O₃ + SO₂ + SO₃

Q14. Neutralization reaction (2 Marks)

Reaction between acid and base forming salt and water.

Example:
HCl + NaOH → NaCl + H₂O

Q15. Oxygen & Sulphur (2 Marks)

O (Z=8) → 2,6
S (Z=16) → 2,8,6

More electronegative → Oxygen

Q16 (i) Amphoteric oxides (2 Marks)

Oxides which react with both acids and bases.

Examples:
Al₂O₃, ZnO

Q16 (ii) Malleability & Ductility (2 Marks)

Malleability → Can be beaten into sheets (Gold)
Ductility → Drawn into wires (Copper)

Q17. Complete reactions (3 Marks)

(i) CH₃COOH + NaHCO₃ →
CH₃COONa + H₂O + CO₂

(ii) 2Na + 2C₂H₅OH →
2C₂H₅ONa + H₂

(iii) C₂H₅OH → (Hot conc. H₂SO₄)
C₂H₄ + H₂O

Q17 (b)(i) Structure of Benzene

Draw hexagonal ring with alternate double bonds.

Q17 (b)(ii) Micelles (2 Marks)

Micelles are clusters of soap molecules formed in water.
They trap oil particles and help in cleaning.

Q18. Names of compounds

(i) CH₃COCH₃ → Propanone
(ii) CH₃CH₂OH → Ethanol
(iii) CH₃CH₂COOH → Propanoic acid

Q19. Addition reaction (2 Marks)

Reaction in which atoms add across double bond.

Example:
CH₂=CH₂ + H₂ → CH₃–CH₃

✳ SECTION – C (BIOLOGY)

Q18. Insulin secreted by →

(D) Pancreas

Q19. Multiple fission →

(D) Plasmodium

Q20. Natural ecosystem →

(D) Pond

Q21. Full form of CFCs →

Chlorofluorocarbons

Q22. Structure protecting spinal cord →

Vertebral column

Q23. Central nervous system (2 Marks)

Parts:

  1. Brain

  2. Spinal cord

Functions: Control & coordination.

Q24. Spore formation in Rhizopus (2 Marks)

Rhizopus forms spores in sporangia.
Spores are released and grow into new organisms.

Q25. Female reproductive part of flower (2 Marks)

Called Pistil
Parts:

  1. Stigma

  2. Style

  3. Ovary

Q26. Mendel’s law of independent assortment (4 Marks)

Traits are inherited independently of each other.
Based on dihybrid cross (RrYy × RrYy)
F₂ ratio = 9:3:3:1

Q27. Human excretory system (6 Marks)

Parts:

  • Kidneys

  • Ureter

  • Urinary bladder

  • Urethra

Functions:

  1. Removal of nitrogenous waste

  2. Osmoregulation

  3. Maintain water balance

📘 HBSE Class 10 Science 2025

पूरा पेपर Section-wise, Board Answer Format में सॉल्व किया गया है।

✳ SECTION – A (PHYSICS)

Q1.

Image always erect in mirror →
Plane mirror & Convex mirror
Ans: (D) Either plane or convex

Q2.

220 V, 100 W bulb operated at 110 V

Power ∝ V²

P₂ = P₁ (V₂/V₁)²
= 100 (110/220)²
= 100 (1/2)²
= 100 × 1/4
= 25 W

Ans: (D) 25 W

Q3.

Small unit of electric power →
Watt

Q4.

Gas filled in electric bulb →
Nitrogen (or Argon)

Q5. Assertion–Reason

Accommodation = change in focal length
Both true & correct explanation
Ans: (A)

Q6. Why sky appears dark to astronaut? (2 Marks)

No atmosphere in space → No scattering → Sky appears black.

Q7. Factors affecting resistance (2 Marks)

  1. Length

  2. Area of cross-section

  3. Nature of material

  4. Temperature

Q8. Ohm’s Law (3 Marks)

Ohm’s law:
V ∝ I

V = IR

Correct equation → R = V/I

Q9 (a) Magnetic field lines (3 Marks)

Properties:

  1. Originate from North & end at South

  2. Never intersect

  3. Closer lines → stronger field

(Draw bar magnet diagram)

Q10 (a) Principal focus of concave mirror (2 Marks)

Point where parallel rays meet after reflection.

Q10 (b) Mirror giving erect enlarged image →

Concave mirror

Q10 (c) Why convex mirror used as rear view mirror? (2 Marks)

  1. Wide field of view

  2. Erect image

OR

(i) 1 Dioptre → Power of lens with focal length 1 m
(ii) f = –2 m

Power = 1/f
= 1 / –2
= –0.5 D

Lens formula:
1/f = 1/v – 1/u

Mirror formula:
1/f = 1/v + 1/u

✳ SECTION – B (CHEMISTRY)

Q11.

Dilute HCl + Iron →
Hydrogen gas + Iron chloride
Ans: (A)

Q12. Prevent Namkeen from rancidity →

All of the above
Ans: (D)

Q13. Most malleable metal →

Gold

Q14. Ionic compounds high melting point →

Strong electrostatic forces.

Q15. Assertion–Reason

HCl turns blue litmus red
Reason false
Correct → (C)

Q16. Combination reaction (2 Marks)

Two or more substances combine to form one product.

Example:
CaO + H₂O → Ca(OH)₂

Q17. Bleaching powder (2 Marks)

Formula → CaOCl₂

Uses:

  1. Disinfect water

  2. Bleaching cotton/linen

Q18. Word & Balanced equations (3 Marks)

(a) Zn + H₂SO₄ → ZnSO₄ + H₂

(b) Mg + 2HCl → MgCl₂ + H₂

(c) Fe + 2HCl → FeCl₂ + H₂

Q19. Electron dot structure (3 Marks)

Na → 1 valence electron
O → 6 valence electrons
Mg → 2 valence electrons

(Draw dot structures)

Q20 (a) Properties of carbon (2 Marks)

  1. Catenation

  2. Tetravalency

Q20 (b) Ethanol vs Ethanoic acid (3 Marks)

Ethanol Ethanoic Acid
Neutral Acidic
No reaction with NaHCO₃ Produces CO₂
Pleasant smell Sour smell

OR

Polymerization → Formation of polymer from monomers
Soap cleaning → Micelle formation

✳ SECTION – C (BIOLOGY)

Q21. Male reproductive system part →

Vas deferens

Q22. Not environment friendly →

Balloon

Q23. CFC harms →

Ozone layer

Q24. Thyroid gland needs →

Iodine

Q25. Assertion–Reason

Hormones responsible for growth
Correct → (A)

Q26. Role of brain in reflex action (2 Marks)

Brain coordinates voluntary actions; reflex mainly through spinal cord.

Q27. Seminal vesicles & prostate gland (2 Marks)

Secrete seminal fluid
Provide nourishment & mobility to sperms.

Q28. L.S. of flower (3 Marks)

Label:
Sepal, Petal, Stamen, Pistil

(Draw diagram)

Q29. Mendel Dihybrid Cross (3 Marks)

Round (RR) Green (yy) × Wrinkled (rr) Yellow (YY)

F₁ → RrYy (Round, Yellow)

Show Punnett square.

Q30 (a) Autotrophic vs Heterotrophic (2 Marks)

Autotrophic Heterotrophic
Make own food Depend on others
Photosynthesis No photosynthesis

Q30 (b) Human digestive system (3 Marks)

Parts:
Mouth → Oesophagus → Stomach → Small intestine → Large intestine

🔁 REPEATED QUESTIONS (YEAR IN BRACKETS)

🔵 PHYSICS

1️⃣ Rear View Mirror (2021, 2024, 2025)

Convex mirror + Reason

2️⃣ Laws of Reflection/Refraction (2023, 2024)

3️⃣ Focal Length / Mirror Formula / Lens Formula (2023, 2024, 2025)

4️⃣ Ohm’s Law (2025) + Resistance Concept (2024, 2025)

5️⃣ Scattering / Sky Colour / Red Sunrise (2021, 2024, 2025)

6️⃣ Magnetic Field Lines (2024, 2025)

7️⃣ Electric Motor Principle (2023)

🟡 CHEMISTRY

1️⃣ Ionic Compounds – High Melting Point (2024, 2025)

2️⃣ Baking Soda / Bleaching Powder (2023, 2024, 2025)

3️⃣ Displacement Reaction (2024, 2025)

4️⃣ Neutralization Reaction (2023, 2025)

5️⃣ Carbon – Catenation & Tetravalency (2025)

6️⃣ Ethanol & Ethanoic Acid (2023, 2025)

7️⃣ Homologous Series (2024)

8️⃣ Electron Dot Structure (2024, 2025)

9️⃣ Balanced Chemical Equations (Every Year)

🟢 BIOLOGY

1️⃣ Male/Female Reproductive System (2021, 2023, 2024, 2025) 🔥🔥🔥

2️⃣ Mendel’s Law of Independent Assortment (2023, 2024, 2025)

3️⃣ Food Chain (2021, 2024)

4️⃣ Ozone Layer & CFC (2023, 2024, 2025)

5️⃣ Thyroid & Iodine (2024, 2025)

6️⃣ Human Excretory System (2023)

7️⃣ Plant Hormones (2024, 2025)

8️⃣ Autotrophic Nutrition (2021, 2024)

⭐ MOST IMPORTANT QUESTIONS (80% Guaranteed Zone)

🔴 Physics Top Priority

  1. Mirror & Lens Numericals

  2. Ohm’s Law

  3. Power Formula

  4. Magnetic Field Lines

  5. Scattering of Light

  6. Electric Motor

🟠 Chemistry Top Priority

  1. Types of Reactions (Combination, Displacement, Neutralization)

  2. Carbon Compounds

  3. Bleaching Powder

  4. pH Based Questions

  5. Ionic Compounds

  6. Micelles

🟢 Biology Top Priority

  1. Mendel Dihybrid Cross

  2. Human Reproductive System

  3. Reflex Action

  4. Endocrine Glands

  5. Human Digestive System

  6. Photosynthesis Conditions

📈 STRONGEST REPEAT AREA (MOST SAFE)

🔥 Reproduction (Every Year)
🔥 Carbon Compounds (Every Year)
🔥 Light Chapter (Every Year)
🔥 Electricity Numericals (Every Year)
🔥 Assertion–Reason (Every Year)

🎯 2026 PREDICTION (Based on Trend)

Very High Probability:

  • Ray Diagram (Mirror/Lens)

  • 3 Mark Numerical (Electricity)

  • Mendel Cross (3 or 4 marks)

  • Electron Dot Structure

  • Acid + Base Reaction

  • Digestive / Excretory System Diagram

📌 FINAL CONCLUSION

If a student prepares:

✔ Light + Electricity
✔ Carbon Compounds
✔ Reproduction
✔ Chemical Reactions
✔ Control & Coordination

🔥 HBSE Class 10 Science

🎯 RAPID FIRE – 100 MCQs (2026 Most Expected)

(Physics + Chemistry + Biology | Board Pattern Based)

🔵 PHYSICS (1–35)

  1. Focal length of concave mirror is taken as:
    (A) Positive (B) Negative (C) Zero (D) Infinite

  2. Unit of power is:
    (A) Volt (B) Ampere (C) Watt (D) Ohm

  3. Rear view mirror is:
    (A) Concave (B) Convex (C) Plane (D) Cylindrical

  4. SI unit of electric current:
    (A) Coulomb (B) Ampere (C) Volt (D) Watt

  5. Formula of resistance:
    (A) V/I (B) I/V (C) VI (D) V²

  6. Sky appears blue due to:
    (A) Reflection (B) Refraction (C) Scattering (D) Dispersion

  7. 1 Dioptre equals:
    (A) 1 m (B) 1/m (C) 1 cm (D) 1 cm⁻¹

  8. Power = ?
    (A) V/I (B) VI (C) I²R (D) Both B & C

  9. Ohm’s law states:
    (A) V ∝ I (B) I ∝ V² (C) R ∝ I (D) V ∝ R

  10. Magnetic field lines never:
    (A) Curve (B) Intersect (C) Form loops (D) Bend

  11. Image always erect in:
    (A) Concave mirror (B) Convex mirror (C) Plane mirror (D) Both B & C

  12. Electric motor converts:
    (A) Mechanical to electrical
    (B) Electrical to mechanical
    (C) Heat to light
    (D) Chemical to electrical

  13. Stars twinkle due to:
    (A) Reflection (B) Refraction (C) Atmospheric refraction (D) Dispersion

  14. Resistance depends on:
    (A) Length (B) Area (C) Temperature (D) All

  15. R = 20Ω, V = 10V, I = ?
    (A) 2A (B) 0.5A (C) 10A (D) 20A

🟠 CHEMISTRY (36–70)

  1. Baking soda formula:
    (A) Na₂CO₃ (B) NaHCO₃ (C) CaCO₃ (D) NaCl

  2. pH less than 7 means:
    (A) Basic (B) Neutral (C) Acidic (D) Salt

  3. Combination reaction:
    (A) A+B→C (B) A→B+C (C) AB+CD (D) None

  4. Rusting is example of:
    (A) Reduction (B) Oxidation (C) Neutralization (D) Addition

  5. Bleaching powder formula:
    (A) CaOCl₂ (B) NaCl (C) CaCO₃ (D) Na₂CO₃

  6. Ionic compounds have:
    (A) Low melting point
    (B) High melting point
    (C) No bonds
    (D) Weak force

  7. Most malleable metal:
    (A) Iron (B) Gold (C) Copper (D) Zinc

  8. Ethanol functional group:
    (A) –COOH (B) –OH (C) –CHO (D) –CO–

  9. Homologous series difference:
    (A) CH₄ (B) CH₂ (C) CO₂ (D) H₂

  10. Catenation property shown by:
    (A) Oxygen (B) Carbon (C) Nitrogen (D) Sulphur

  11. Acid turns blue litmus:
    (A) Blue (B) Red (C) Green (D) Yellow

  12. pH of pure water:
    (A) 5 (B) 6 (C) 7 (D) 8

  13. Displacement reaction example:
    (A) Zn + CuSO₄
    (B) HCl + NaOH
    (C) CaO + H₂O
    (D) None

  14. Ethanoic acid reacts with NaHCO₃ to produce:
    (A) O₂ (B) CO₂ (C) H₂ (D) N₂

  15. Sodium stored in:
    (A) Water (B) Oil (C) Kerosene (D) Air

🟢 BIOLOGY (71–100)

  1. Autotrophs prepare food by:
    (A) Respiration (B) Photosynthesis (C) Digestion (D) Excretion

  2. Insulin secreted by:
    (A) Liver (B) Kidney (C) Pancreas (D) Heart

  3. Unit of heredity:
    (A) Cell (B) Gene (C) Tissue (D) Organ

  4. Law of independent assortment ratio:
    (A) 3:1 (B) 9:3:3:1 (C) 1:2:1 (D) 2:1

  5. Human male chromosome:
    (A) XX (B) XY (C) YY (D) XO

  6. CFC damages:
    (A) Ozone (B) Water (C) Soil (D) Plants

  7. Thyroid needs:
    (A) Calcium (B) Iron (C) Iodine (D) Sodium

  8. Reflex action controlled by:
    (A) Brain (B) Spinal cord (C) Heart (D) Kidney

  9. Food chain starts with:
    (A) Carnivore (B) Producer (C) Herbivore (D) Omnivore

  10. Longest part of alimentary canal:
    (A) Stomach (B) Small intestine (C) Large intestine (D) Oesophagus

🔥 ANSWER KEY

1-B
2-C
3-B
4-B
5-A
6-C
7-B
8-D
9-A
10-B
11-D
12-B
13-C
14-D
15-B

36-B
37-C
38-A
39-B
40-A
41-B
42-B
43-B
44-B
45-B
46-B
47-C
48-A
49-B
50-C

71-B
72-C
73-B
74-B
75-B
76-A
77-C
78-B
79-B
80-B

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