Tamil Nadu Class 9 Science Model Paper 2 — Samacheer Kalvi

Instructions

• Section A: 15 × 1 = 15 marks
• Section B: 8 × 3 = 24 marks (Answer any 8 out of 10)
• Section C: 4 × 5 = 20 marks (Answer any 4 out of 5)
• Section D: 1 × 16 = 16 marks

Section A — One Mark Questions (15 marks)

1. Define velocity. 2. State Archimedes' principle in one sentence. 3. What is the least count of a Vernier caliper? 4. Name the process by which solid CO₂ directly becomes gas. 5. What is the atomic number of Sodium? 6. Name the scientist who proposed the Modern Periodic Law. 7. Define echo. 8. State the SI unit of resistance. 9. What is the general formula for alkanes? 10. Name the tissue that transports food in plants. 11. Define reflex action. 12. Which mineral deficiency causes Goitre? 13. Name the type of reaction: Fe + CuSO₄ → FeSO₄ + Cu. 14. What are the two main classes of angiosperms? 15. Define solubility.

Section B — Short Answer Questions (3 marks each, answer any 8)

1. Explain the factors that affect solubility. How does temperature affect the solubility of solids vs gases? 2. A body is submerged in water. Its weight in air is 600 N and in water is 500 N. Find the buoyant force and comment on its density. 3. Distinguish between saturated and unsaturated hydrocarbons. Give one example of each. 4. Explain how reflex action works. Draw the reflex arc. 5. State Mendeleev's periodic law. Give two merits and two defects. 6. Distinguish between echo and reverberation. What condition is needed for echo? 7. A current of 2 A flows through a resistance of 10 Ω for 5 minutes. Find the heat produced. 8. Explain the five types of chemical reactions with equations. 9. Write the names and functions of the three main parts of the brain. 10. Calculate the mass percentage of 5 g of salt dissolved in 95 g of water.

Section C — Long Answer Questions (5 marks each, answer any 4)

1. Explain Archimedes' principle. Describe an experiment to verify it. Give three applications. 2. Describe the Bohr model of the atom. Compare it with Rutherford's model. What are its limitations? 3. Explain the classification of animals. Describe the five classes of vertebrates with features and examples. 4. What is Joule's law of heating? Explain the heating effect of electric current and list its applications. What is a fuse and how does it work? 5. Explain nutrition in humans. Describe the six classes of nutrients with functions and sources. What are deficiency diseases?

Section D — Extended Response (16 marks)

Choose one of the following:

Option 1: Explain the modern periodic table in detail — its structure, periods, groups, and the four periodic trends (atomic radius, ionisation energy, electronegativity, metallic character). Use diagrams and examples.

Option 2: Write a detailed essay on the nervous system — its divisions, structure of a neuron (with diagram), brain functions (cerebrum, cerebellum, medulla), reflex action (with diagram), and the importance of the nervous system.

Time Management Plan

Correction Plan

After attempting this paper, list all errors. Focus on:

• Chapters where more than 2 marks were lost
• Numericals where the formula was wrong
• Diagrams that were incomplete
• Definitions that missed key words