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IGCSE Physics Comprehensive Revision Guide

May 4, 2025

IGCSE Physics (9-1) Revision Notes

Section 1: Forces and Motion

Units

  • Mass: Kilogram (kg)
  • Distance: Metre (m)
  • Speed/Velocity: Metre per second (m/s)
  • Acceleration: Metre per second squared (m/s²)
  • Force: Newton (N)
  • Time: Second (s)
  • Gravitational acceleration: Newton per kilogram (N/kg)
  • Momentum: Kilogram metre per second (kg m/s)

Movement and Position

  • Distance: Change in position of an object.
  • Displacement: Change in position in a particular direction.
  • Distance-Time Graphs: Represents speed or velocity; slope = speed.
  • Velocity-Time Graphs: Show acceleration; area under graph = distance travelled.
  • Speed: Rate of change of distance; average speed = total distance/total time.
  • Velocity: Speed in a specific direction.

Forces, Movement, Shape, and Momentum

  • Effects of Forces: Change in speed, shape, or direction.
  • Types of Forces: Gravitational, normal reaction, air resistance, upthrust, magnetic, electrostatic, tension, frictional.
  • Friction: Opposes motion; types include kinetic, static, rolling, fluid.
  • Newton's Laws: 3rd Law - For every action, there is an equal and opposite reaction.
  • Momentum: Product of mass and velocity; conserved in collisions.

Experiments

  • Measuring Speed: Using stopwatches, light gates, ticker tapes.
  • Measuring Acceleration: Using video sequences, modern Galileo experiments.
  • Investigating Friction: Effects of mass, surface roughness.
  • Investigating Forces: Using pulleys and trolleys to study F ∝ a.

Section 2: Electricity

Units

  • Current: Ampere (A)
  • Charge: Coulomb (C)
  • Energy: Joule (J)
  • Resistance: Ohm (Ω)
  • Voltage: Volt (V)
  • Power: Watt (W)

Mains Electricity

  • Hazards: Frayed cables, water around sockets, metal objects in sockets.
  • Safety Devices: Fuses, circuit breakers, insulation, earthing.
  • Current in Resistors: Converts electrical energy to heat.
  • AC vs DC: AC changes direction; DC flows in one direction.

Circuits

  • Series Circuits: Shared voltage, if one component fails, all fail.
  • Parallel Circuits: Same voltage across branches; components can be controlled independently.
  • Ohm’s Law: V = IR; describes voltage, current, resistance relationship.

Experiments

  • Investigating Ohm’s Law: Measuring current and voltage across resistors.
  • Effect of Resistance: Higher resistance means lower current.

Section 3: Waves

Units

  • Frequency: Hertz (Hz)
  • Wavelength: Metre (m)
  • Wave speed: Metre per second (m/s)

Properties of Waves

  • Transverse vs Longitudinal: Transverse - vibrations perpendicular; Longitudinal - vibrations parallel.
  • Energy Transfer: Waves transfer energy but not matter.
  • Wave Equation: v = fλ (speed = frequency × wavelength)

Electromagnetic Spectrum

  • Continuous Spectrum: Includes radio waves to gamma rays; light is visible spectrum.
  • Uses: Radio - communication; Microwaves - cooking, communication; Infrared - heating, night vision.
  • Dangers: UV - skin cancer; X-rays - cancer risk; Gamma - cell damage.

Light and Sound

  • Reflection and Refraction: Light changes direction on passing through different media.
  • Sound Waves: Longitudinal; can be reflected, refracted, diffracted.

Section 4: Energy Resources and Energy Transfer

Units

  • Energy: Joule (J)
  • Power: Watt (W)

Energy Transfer

  • Forms of Energy: Thermal, light, electrical, sound, kinetic, chemical, nuclear, potential.
  • Conservation of Energy: Energy is not created or destroyed, only transformed.
  • Efficiency: Ratio of useful energy output to total energy input.

Work and Power

  • Work: Force x Distance; measured in joules.
  • Power: Rate of energy transfer; Power = Work/Time.

Energy Resources

  • Renewable: Solar, wind, hydroelectric, geothermal; clean but variable.
  • Non-renewable: Fossil fuels, nuclear; reliable but polluting.

Section 5: Solids, Liquids, and Gases

Units

  • Pressure: Pascal (Pa)
  • Density: Kilogram per cubic metre (kg/m³)

Density and Pressure

  • Density: Mass/Volume.
  • Pressure: Force/Area; acts in all directions in fluids.

Change of State

  • Melting, Boiling, Evaporation: Heat increases particle movement; change state.
  • Particle Arrangements: Solids - fixed; Liquids - flow; Gases - spread out.

Section 6: Magnetism and Electromagnetism

Magnetism

  • Magnetic Fields: Produced by magnets and electric currents.
  • Electromagnets: Temporary magnets created with electric current.

Electromagnetism

  • Current in Magnetic Field: Experiences a force; basis of motors and speakers.
  • Induced Voltage: Voltage induced by changing magnetic field; basis of generators.

Section 7: Radioactivity and Particles

Radioactivity

  • Radiation Types: Alpha, beta, gamma.
  • Radioactive Decay: Random process, measured in Becquerels.
  • Half-Life: Time for activity to reduce to half.

Uses of Radioactivity

  • Medical: Tracers, radiotherapy.
  • Industrial: Tracing leaks, thickness gauges.
  • Dating: Carbon dating for age estimation.

Section 8: Astrophysics

Stellar Evolution

  • Star Lifecycle: From nebula to black hole or dwarf star.
  • Galaxies and Universe: Galactic structures, universe expansion.

Cosmology

  • Big Bang Theory: Universe origin theory; supported by redshift observations.