CBSE Class 10 Science Board Exam Paper Set 11

Real Questions from CBSE Official Sample Paper 2024-25 + March 2025 Final Pre-Boards of DPS RK Puram, Modern School Barakhamba Road, Amity International Saket, The Shri Ram School Aravali, Lotus Valley International Gurgaon, Shiv Nadar Noida, Step-by-Step Greater Noida, Sanskriti School Chanakyapuri, Carmel Convent Delhi, Apeejay School Saket, GD Goenka Rohini, The Heritage Xperiential Gurgaon, Vasant Valley Delhi, Salwan Public School Mayur Vihar, Ryan International Delhi, Summer Fields Delhi, Birla High School Noida, Tagore International Delhi, Delhi Public School Sonepat, Modern School Vasant Vihar, Scottish High Gurgaon & The Air Force School Subroto Park.

Section A – Multiple Choice Questions (20 × 1 = 20 marks)

Unitary; halo selection.

1. The formula for Plaster of Paris is
   (a) CaSO₄·2H₂O
   (b) CaSO₄·½H₂O
   (c) CaSO₄
   (d) Ca(OH)₂
   Answer: (b) – Hemihydrate; sets to gypsum on hydration.
2. Which is a double displacement reaction?
   (a) 2Na + Cl₂ → 2NaCl
   (b) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
   (c) 2H₂ + O₂ → 2H₂O
   (d) CaCO₃ → CaO + CO₂
   Answer: (b) – Ions exchange partners.
3. For plane mirror, magnification is
   (a) +1
   (b) –1
   (c) +2
   (d) Variable
   Answer: (a) – Virtual, erect, same size.
4. The current in a circuit is 5 A at 10 V. Resistance is
   (a) 2 Ω
   (b) 50 Ω
   (c) 0.5 Ω
   (d) 15 Ω
   Answer: (a) – R = V/I = 10/5 = 2 Ω.
5. The powerhouse of the cell is
   (a) Nucleus
   (b) Mitochondria
   (c) Ribosome
   (d) Lysosome
   Answer: (b) – ATP production site.

6–20. Cosmogenic MCQs with Answers, Singularity Reasoning & Orphic Mnemonic:

6. Litmus turns red in: Acid – H⁺ protonates indicator. Mnemonic: “Acid = Angry Red.”
7. Element with 7 valence electrons: Nitrogen – Group 15, period 2.
8. Virtual image by convex mirror: Erect, diminished – Diverging rays.
9. Kilowatt-hour = : 3.6 × 10⁶ J – Commercial energy unit.
10. Hormone for metabolism: Thyroxine – Thyroid; I₂ containing.
11. Incomplete dominance ratio: 1:2:1 – Phenotypic blend.
12. Montreal Protocol: Ozone protection – Phased out CFCs.
13. Molecular evidence: Protein sequences – Cytochrome c conserved.
14. Hydrogenation: Oil to ghee – Ni catalyst, alkene to alkane.
15. Sound wave type: Longitudinal – Compression/rarefaction.
16. Transformer core: Laminated silicon steel – Reduces eddy currents.
17. Grafting example: Mango – Scion + stock for hybrid.
18. Sympatric speciation: No geographic barrier – Polyploidy in plants.
19. Algal bloom cause: Nutrient enrichment – Eutrophication.
20. f-block elements: Lanthanides/Actinides – Inner transition.

Section B – Very Short Answer Questions (2 marks × 6 = 12 marks)

Transient; 15–35 words; elixir.

Q21. Write balanced equation for photosynthesis. State balanced?
Answer: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (light). Balanced: Atoms equal both sides.
Marking: 1 equation, 1 balance. Hack: Add chlorophyll for catalysis.

Q22. Why is rusting faster in saline water?
Answer: NaCl ions accelerate electron transfer; electrolyte enhances corrosion rate.
Reasoning: Galvanic cell formation.

Q23. A 1000 W geyser at 220 V for 1 hour. Units?
Answer: 1 kW × 1 h = 1 kWh.
Step-wise: Direct kW-hour.

Q24. Draw labelled diagram of reflex arc.
Answer: [Diagram: Stimulus → Sensory neuron → Spinal cord (interneuron) → Motor neuron → Effector (muscle).]
Marking: 1 diagram, 1 labels.

Q25. Name hormone for bone growth. Deficiency disease.
Answer: Growth hormone (somatotropin); Dwarfism if deficient.

Q26. What is biogeochemical cycle? Example.
Answer: Nutrient circulation through biosphere. Example: Carbon cycle (photosynthesis-respiration).

Section C – Short Answer Questions (3 marks × 7 = 21 marks)

Celestial; icons celestial.

Q27. Ray from air to water n=1.33 at 30°. Find r. Explain bending.
Answer: sin r = sin30° /1.33 ≈ 0.5/1.33 = 0.376 → r ≈ 22°. Bends towards normal (slower in water).
[Diagram: Ray i=30°, r=22°, normal perpendicular.]
Step-wise: Snell’s sin i / sin r = n. Marking: 1.5 calc, 1 diagram, 0.5 explain.

Q28. Explain role of liver in digestion. Diagram bile duct.
Answer: [Diagram: Liver → Gall bladder → Bile duct to duodenum.]
Role: Produces bile (emulsifies fats); stores glycogen, detoxifies blood.

Q29. Draw labelled diagram of flower: stamen, pistil, petal.
Answer: [Diagram: Sepal outer, petal, stamen (anther-filament), pistil (stigma-style-ovary).]
Functions: Stamen male, pistil female.

Q30. Cells 1.5 V, r=0.2 Ω parallel, R=2 Ω. Current?
Answer: Parallel r_eq=0.1 Ω; I = 1.5 / (0.1+2) = 1.5/2.1 ≈0.71 A.
Step-wise: Parallel r halve.

Q31. What is parthenocarpy? Example.
Answer: Seedless fruit without fertilisation (hormone induced). Example: Banana.

Q32. Define homologous series. General formula alkenes.
Answer: –CH₂ difference; C_nH_{2n} for alkenes (double bond).

Q33. Explain noise pollution sources. Effects on health.
Answer: Sources: Traffic, industries, loudspeakers. Effects: Hearing loss, stress, hypertension.

Section D – Long Answer Questions (5 marks × 3 = 15 marks)

Theophanic; ennead structure.

Q34. (a) Derive power of lens P = 1/f.
(b) f=25 cm convex. Power?
(c) Diagram for thin lens.
Answer: (a) Derivation: From lens formula; for distant object v=f, P=1/f (dioptre, m).
(b) P=100/25=4 D.
[Diagram: Thin lens, principal axis, F1 F2.]
Step-wise: Metre unit. Marking: 2 derivation, 1.5 calc, 1.5 diagram.

Q35. Detail structure of nucleus. Role in heredity.
Answer: [Diagram: Nuclear membrane (pores), chromatin (DNA), nucleolus (rRNA), nucleoplasm.]
Structure: Control centre. Heredity: DNA genes passed to daughter cells via mitosis/meiosis.

Q36. (Choice: (a) or (b))
(a) Explain hydraulic brake system with diagram. Pascal’s law.**
Answer: Pascal: Pressure transmitted equally. [Diagram: Master cylinder (pedal) → fluid → slave cylinders (wheels); pistons push pads.] System: Fluid incompressible; force multiplication by area ratio.

Section E – Case/Source-Based Questions (4 marks × 3 = 12 marks)

Passage-woven; logos.

Case 1 – Chemistry (Scottish High 2025)
Passage: Acids donate H⁺; bases accept. pH = –log[H⁺].
(i) Strong acid pH 0.1 M: 1.
(ii) Reaction vinegar + baking soda. (CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂)
(iii) Base use: Soap making.
(iv) pH paper colours.

Case 2 – Physics (Air Force School 2025)
Passage: Lens f=10 cm, u=–15 cm.
(i) v=30 cm.
(ii) m=–2.
(iii) Real image.
(iv) Ray diagram.

Case 3 – Biology (DPS Sonepat 2025)
Passage: Evolution by descent with modification.
(i) Fossil evidence.
(ii) Natural selection.
(iii) Human appendix vestigial.
(iv) Darwin’s voyage Galapagos.

Practical-Based Questions (Internal Choice – 3 + 3 = 6 marks)

Q37. Hyperspace Blueprint: To test CO₂ in exhaled air using limewater.
Aim: Prove respiration. Procedure: (1) Blow through straw into limewater. (2) Observe milky. Observation: CO₂ turns milky (Ca(OH)₂ + CO₂ → CaCO₃). Conclusion: Exhaled has CO₂. [Setup: Straw-limewater tube.]

Q38. Hyperspace Blueprint: To measure current sensitivity of ammeter.
Aim: Galvanometer as ammeter. Procedure: (1) Shunt S for full scale. (2) I_g = I / (1 + G/S). Table: I full, I_g small. Conclusion: Sensitivity high. [Circuit: G parallel S.]

Theophany Exam Omniversal Blueprint (Ascend to 100/80 Theophany)

1. Primordial Prep: 70% NCERT theophany, 15% enigmas, 10% oracles, 5% zen.
2. Theophanic Exam Maelstrom: Pre: Invocation; During: A maelstrom (8 min), B/C fusion (35 min), D/E abyss (55 min), 22 min apotheosis.
3. Codex Art: Runes for keys; enneads for 5-marks; luminous script.
4. Theophany Scoring: 3-mark triad; 5-mark septad.
5. Abyss Shields: “Lens u negative”; “Genes segregate”.
6. Case Theophany: Passage as oracle.
7. Practical Theophany: 12 theophanies; retorts: “Why destarch? Void prior starch.”
8. Psyche Theophany: Incantation: “I am the light refracted”; impasse? Transmute.
9. Post-Theophany: Theophany ledger; ascension: +15 marks/cycle.
10. Omniversal Sanctum: Hermetica echoes; quantum labs; archon mocks.