SS 2
Revision – First Term
Physics
SS 2
First Term
📌 Welcome to Your First Term Revision!
This comprehensive revision covers all the topics from the First Term. Use this to:
- Review key concepts from each topic
- Practice with revision questions
- Prepare for your end-of-term examination
- Identify areas that need more attention
Topics Covered in First Term
| Week |
Topic |
Key Concepts |
| 1 |
Heat and Temperature |
Difference between heat and temperature, thermometers, temperature scales (Celsius, Fahrenheit, Kelvin) |
| 2 |
Thermal Expansion |
Expansion of solids, liquids, gases; bimetallic strips; applications and consequences |
| 3 |
Thermal Conductivity |
Conductors and insulators; factors affecting thermal conductivity |
| 4 |
Gas Laws |
Boyle's Law, Charles' Law, Pressure Law; The General Gas Equation |
| 5 |
Evaporation and Boiling |
Differences; factors affecting evaporation; latent heat |
| 6 |
Structure of Matter |
Atomic structure; kinetic theory; states of matter; Brownian motion |
| 7 |
Work, Energy and Power |
Definition of work; forms of energy; conservation of energy; power |
| 8 |
Simple Machines |
Levers, pulleys, inclined planes, screws, wedges; MA, VR, efficiency |
| 9 |
Light: Reflection |
Laws of reflection; plane mirrors; spherical mirrors (concave and convex) |
| 10 |
Light: Refraction |
Laws of refraction; refractive index; prisms; dispersion of light |
Topic 1: Heat and Temperature – Summary
🔑 Key Points:
- Heat: Energy transferred due to temperature difference (Joules).
- Temperature: Measure of average kinetic energy of particles (Kelvin, Celsius, Fahrenheit).
- Temperature Scales: Celsius (°C), Fahrenheit (°F), Kelvin (K).
- Conversions: K = °C + 273; °F = (9/5)°C + 32
- Thermometers: Mercury, alcohol, thermocouple, resistance, infrared.
Topic 2: Thermal Expansion – Summary
🔑 Key Points:
- Linear Expansion: ΔL = αL₀ΔT
- Area Expansion: ΔA = βA₀ΔT (β ≈ 2α)
- Volume Expansion: ΔV = γV₀ΔT (γ ≈ 3α)
- Bimetallic Strips: Two metals with different expansion coefficients bend when heated (used in thermostats).
- Applications: Rivets, expansion joints, thermostats.
Topic 3: Thermal Conductivity – Summary
🔑 Key Points:
- Conductors: Allow heat to flow easily (e.g., metals like copper, aluminium).
- Insulators: Resist heat flow (e.g., wood, rubber, air).
- Factors affecting conductivity: Material type, temperature difference, cross-sectional area, length.
- Thermal Conductivity (k): Q/t = kA(ΔT)/L
Topic 4: Gas Laws – Summary
🔑 Key Points:
- Boyle's Law: P₁V₁ = P₂V₂ (at constant T)
- Charles' Law: V₁/T₁ = V₂/T₂ (at constant P)
- Pressure Law: P₁/T₁ = P₂/T₂ (at constant V)
- General Gas Equation: P₁V₁/T₁ = P₂V₂/T₂
- Ideal Gas Equation: PV = nRT
Topic 5: Evaporation and Boiling – Summary
🔑 Key Points:
- Evaporation: Surface phenomenon, occurs at any temperature, cooling effect.
- Boiling: Bulk phenomenon, occurs at a specific temperature (boiling point).
- Factors affecting evaporation: Temperature, surface area, humidity, wind speed.
- Latent Heat: Heat required for phase change without temperature change.
- Specific Latent Heat of Fusion: Lf; Vaporization: Lv
Topic 6: Structure of Matter – Summary
🔑 Key Points:
- Atomic Structure: Nucleus (protons + neutrons) + electrons.
- Kinetic Theory: Particles in constant random motion.
- States of Matter: Solid (fixed shape), Liquid (flow), Gas (fill container).
- Brownian Motion: Random motion of particles in a fluid due to collisions.
Topic 7: Work, Energy and Power – Summary
🔑 Key Points:
- Work: W = F × d × cos θ (Joules).
- Energy: Capacity to do work. Forms: Kinetic, Potential, Thermal, Chemical, etc.
- Conservation of Energy: Energy cannot be created or destroyed, only converted.
- Power: P = W/t = F × v (Watts).
- Kinetic Energy: Ek = ½mv²
- Potential Energy: Ep = mgh
Topic 8: Simple Machines – Summary
🔑 Key Points:
- Mechanical Advantage (MA): Load / Effort
- Velocity Ratio (VR): Distance moved by effort / Distance moved by load
- Efficiency: η = (MA/VR) × 100%
- Levers: First, second, third class.
- Pulleys: MA = number of rope segments supporting load.
- Inclined Plane: MA = length/height
Topic 9: Reflection of Light – Summary
🔑 Key Points:
- Laws of Reflection: (1) Angle of incidence = angle of reflection. (2) Incident ray, reflected ray, normal lie in the same plane.
- Plane Mirror: Image is virtual, same size, laterally inverted.
- Concave Mirror: Converging; used in telescopes, shaving mirrors.
- Convex Mirror: Diverging; used in car side mirrors, security mirrors.
- Mirror Formula: 1/f = 1/u + 1/v
Topic 10: Refraction of Light – Summary
🔑 Key Points:
- Laws of Refraction: Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
- Refractive Index: n = c/v = sin i / sin r
- Prisms: Dispersion of white light into spectrum (VIBGYOR).
- Total Internal Reflection: Occurs when angle of incidence > critical angle.
Key Formulas Summary
| Topic |
Formula |
Variables |
| Temperature Conversion |
K = °C + 273 |
K = Kelvin, °C = Celsius |
| Linear Expansion |
ΔL = αL₀ΔT |
α = coefficient of linear expansion |
| Thermal Conductivity |
Q/t = kA(ΔT)/L |
k = thermal conductivity |
| Boyle's Law |
P₁V₁ = P₂V₂ |
P = pressure, V = volume |
| General Gas Equation |
P₁V₁/T₁ = P₂V₂/T₂ |
T = temperature (K) |
| Work |
W = F × d × cos θ |
F = force, d = distance |
| Kinetic Energy |
Ek = ½mv² |
m = mass, v = velocity |
| Potential Energy |
Ep = mgh |
g = 9.8 m/s², h = height |
| Power |
P = W/t |
W = work, t = time |
| Mirror Formula |
1/f = 1/u + 1/v |
f = focal length, u = object distance |
| Snell's Law |
n₁ sin θ₁ = n₂ sin θ₂ |
n = refractive index |
Revision Questions
Test your understanding of all First Term topics:
Section A: Multiple Choice (Choose the correct option)
- The SI unit of temperature is:
A) Celsius B) Fahrenheit C) Kelvin D) Joule
- Boyle's Law states that at constant temperature:
A) P ∝ V B) P ∝ 1/V C) V ∝ T D) P ∝ T
- The energy possessed by a moving object is called:
A) Potential energy B) Kinetic energy C) Thermal energy D) Chemical energy
- Which of the following is a good conductor of heat?
A) Wood B) Rubber C) Copper D) Plastic
- The angle of incidence is equal to the angle of reflection according to:
A) Snell's Law B) Law of Reflection C) Boyle's Law D) Charles' Law
Answers: 1-C, 2-B, 3-B, 4-C, 5-B
Section B: Short Answer Questions
- Distinguish between heat and temperature.
- State the three gas laws and write their mathematical expressions.
- Explain the difference between evaporation and boiling.
- State the law of conservation of energy.
- Define refractive index and write its formula.
Section C: Calculation Questions
- A metal rod of length 2.0 m increases by 0.002 m when heated from 20°C to 100°C. Calculate the coefficient of linear expansion.
- A gas occupies 500 cm³ at 1 atm pressure. What volume will it occupy at 2.5 atm at constant temperature?
- A 5 kg object is lifted to a height of 10 m. Calculate its potential energy. (g = 10 m/s²)
- A simple machine has a mechanical advantage of 4 and a velocity ratio of 5. Calculate its efficiency.
- An object is placed 15 cm in front of a concave mirror with focal length 10 cm. Calculate the image distance.
Answers to Section B
1. Heat is energy transferred due to temperature difference; temperature is the measure of average kinetic energy of particles.
2. Boyle's: P₁V₁ = P₂V₂; Charles': V₁/T₁ = V₂/T₂; Pressure: P₁/T₁ = P₂/T₂
3. Evaporation occurs at any temperature on the surface; boiling occurs at a specific temperature throughout the liquid.
4. Energy cannot be created or destroyed, only converted from one form to another.
5. n = c/v = sin i / sin r
Answers to Section C
1. α = ΔL/(L₀ΔT) = 0.002/(2.0 × 80) = 1.25 × 10⁻⁵ /°C
2. V₂ = P₁V₁/P₂ = 1 × 500/2.5 = 200 cm³
3. Ep = mgh = 5 × 10 × 10 = 500 J
4. η = (MA/VR) × 100% = (4/5) × 100 = 80%
5. 1/f = 1/u + 1/v → 1/10 = 1/15 + 1/v → v = 30 cm
Examination Preparation Tips
📌 Tips for Success:
- Review all formulas – make a formula sheet and memorise them.
- Understand key definitions – be able to explain concepts in your own words.
- Practice calculations – work through all examples and assignment questions.
- Draw diagrams – practice drawing ray diagrams, mirror diagrams, and machine diagrams.
- Know your units – be familiar with SI units for all quantities.
- Time management – allocate time for each section during the exam.
- Read questions carefully – identify what is being asked before answering.