Exercise Solutions Available
Step-by-step answers for all textbook questions in this chapter
Essential Physics Diagrams
1. Velocity–Time Graph (Motion)
Diagram description:
- X-axis: Time (t) in seconds
- Y-axis: Velocity (v) in m/s
- Uniform acceleration: straight line with positive slope
- Slope = acceleration (a = Δv/Δt)
- Area under graph = displacement
Labels: X-axis (Time in s), Y-axis (Velocity in m/s), slope = a, area = displacement
How to draw: 1. Draw horizontal X-axis and vertical Y-axis 2. Mark a straight line from origin (u) to final velocity (v) 3. Drop perpendicular from v to x-axis 4. Shade area under line = displacement 5. Label all parts
2. Distance–Time Graph (Motion)
- Horizontal straight line = object at rest
- Straight line with positive slope = uniform motion
- Curve (concave up) = accelerating motion
3. Hydraulic Press (Fluids / Pascal's Law)
Labels: Small piston (F₁, A₁), Large piston (F₂, A₂), fluid chamber, direction of force arrows, F₁/A₁ = F₂/A₂
4. Vernier Calliper (Measurement)
Labels: Main scale, vernier scale, fixed jaw, movable jaw, depth rod, object being measured, main scale reading, vernier scale reading
Essential Chemistry Diagrams
5. Bohr Atomic Model — Sodium (Na, Z=11)
How to draw: 1. Draw a circle (nucleus) at centre; write "11p, 12n" inside 2. Draw 3 concentric circles (shells K, L, M) 3. Mark 2 electrons on K shell (×2) 4. Mark 8 electrons on L shell (×8) 5. Mark 1 electron on M shell (×1) 6. Label: K shell (2e), L shell (8e), M shell (1e)
Bohr models needed for Class 9:
- Hydrogen (H, Z=1): 1e on K shell
- Carbon (C, Z=6): 2e K, 4e L
- Oxygen (O, Z=8): 2e K, 6e L
- Sodium (Na, Z=11): 2e K, 8e L, 1e M
- Chlorine (Cl, Z=17): 2e K, 8e L, 7e M
- Calcium (Ca, Z=20): 2e K, 8e L, 8e M, 2e N
6. States of Matter Interconversion
Essential Biology Diagrams
7. Neuron Structure
Labels (must include all):
- Cell body (Soma)
- Nucleus
- Dendrites (short branching projections — receive signals)
- Axon (long fibre — carries signals away from cell body)
- Myelin Sheath (insulating layer)
- Node of Ranvier (gaps in myelin sheath)
- Axon terminal (end knob / terminal bouton)
- Synapse (junction between two neurons)
8. Reflex Arc
Labels:
- Receptor (skin / sensory organ)
- Sensory neuron (afferent)
- Spinal cord (relay centre)
- Motor neuron (efferent)
- Effector (muscle / gland)
- Direction of impulse (arrows)
9. Human Brain (Lateral View)
Labels:
- Cerebrum (largest; thinking, memory, voluntary actions)
- Cerebellum (coordination, balance)
- Medulla Oblongata (breathing, heart rate, automatic functions)
- Pons (connects cerebrum and cerebellum)
- Thalamus / Hypothalamus (if required)
- Brain stem
10. Plant Kingdom Classification Chart
Practical Activity Guide
Activity: Demonstrating Evaporation (Chemistry)
Apparatus: Two petri dishes, water, alcohol Procedure: Place equal amounts in each dish at room temperature. Observe which evaporates faster. Observation: Alcohol evaporates faster due to lower boiling point. Conclusion: Evaporation rate depends on nature of liquid (volatility).
Activity: Verifying Archimedes' Principle (Physics)
Apparatus: Spring balance, object, measuring cylinder, water Procedure: Weigh object in air → weigh submerged in water → measure water displaced. Observation: Loss in weight = weight of water displaced. Conclusion: Archimedes' Principle verified.
Activity: Demonstrating Reflex Action (Biology)
Apparatus: Hammer (reflex hammer), knee of a seated person Procedure: Tap the patellar tendon below the kneecap lightly. Observation: Involuntary forward kick of the leg. Conclusion: Reflex actions occur without conscious brain control — patellar reflex arc.