IGCSE Physics Paper 4 Final Review

Introduction

• Purpose: Final boost for IGCSE Physics Paper 4.
• Content: Recap of essential concepts, definitions, and must-know formulas.

Motion

• Speed: Defined as distance per time (scalar quantity).
• Velocity: Defined as displacement per unit time (vector quantity).
• Acceleration: Rate of change of velocity (vector quantity).
• Average Speed: Total distance traveled per total time.
• Graphs:
  • Distance-Time Graph: Gradient represents speed.
  • Speed-Time Graph: Area under the graph represents total distance; gradient represents acceleration.

Free Fall

• Without Air Resistance: Objects fall with gravitational acceleration (9.8 m/s²).
• With Air Resistance: Air resistance increases as speed increases.
• Terminal Velocity: Maximum velocity when air resistance balances weight; no acceleration.

Mass vs. Weight

• Mass: Amount of substance (scalar), measured in kg using electronic balance.
• Weight: Gravitational force (vector), measured in Newton using a spring balance.

Density

• Definition: Mass per unit volume (scalar).
• Formula: ( \text{Density} = \frac{m}{V} )
• Measuring Density: Use electronic balance for mass, and measuring cylinder or geometric method for volume.

Hook's Law

• Statement: Extension is directly proportional to force applied within the limit of proportionality.
• Limit of Proportionality vs Elastic Limit: Maximum point obeying Hook's law vs point where permanent deformation occurs.
• Formula: ( F = kx ) (Force = spring constant × extension)

Circular Motion

• Centripetal Force: Force causing circular motion, directed towards the center.
• Not a New Force: Can be friction, tension, etc.

Moments

• Definition: Product of force and perpendicular distance from the pivot.
• Principle of Moments: Total clockwise moments = total anticlockwise moments for equilibrium.

Center of Mass vs. Center of Gravity

• Center of Mass: Point where mass is considered to act.
• Center of Gravity: Point where weight is considered to act.

Momentum

• Definition: Product of mass and velocity (vector).
• Impulse: Change in momentum, ( F \times t = \Delta (mv) ).

Work and Energy

• Work: Force times distance moved in force direction, measured in Joules.
• Energy Types:
  • Gravitational Potential Energy (GPE): ( mgh ).
  • Kinetic Energy (KE): ( \frac{1}{2}mv^2 ).

Principle of Conservation of Energy

• Statement: Energy cannot be created or destroyed, only transformed.

Efficiency

• Formula: ( \frac{\text{useful output}}{\text{input}} \times 100% )

Power

• Definition: Work done per unit time.
• Unit: Watt (W).

Pressure

• Definition: Force per unit area.
• Formula for Solids: ( P = \frac{F}{A} ).
• Fluid Pressure: ( P = \rho g h ).

Thermal Physics

• Internal Energy: Sum of kinetic and potential energies of particles.
• Heat Transfer Methods: Conduction, convection, and radiation.
• Boiling vs Evaporation: Boiling at a fixed temperature, evaporation at any temperature.

Waves

• Types: Transverse and longitudinal waves.
• Wave Equation: ( v = f\lambda ) (wave speed = frequency × wavelength).

Reflection and Refraction

• Reflection: Bouncing of waves off a surface; angle of incidence equals angle of reflection.
• Refraction: Bending of waves due to change in speed when passing through different media.

Diffraction

• Definition: Spreading of waves when they pass through a gap.
• Conditions: More significant when gap size is similar to wavelength.

Electromagnetism

• Electromagnetic Induction: EMF induced by changing magnetic field.
• Transformers: Use AC to transfer electrical energy between circuits.

Nuclear Physics

• Radioactive Decay:
  • Alpha: Emission of helium nucleus.
  • Beta: Emission of fast-moving electrons.
  • Gamma: Emission of electromagnetic radiation.
• Half-life: Time for half the radioactive nuclei to decay.

Space Physics

• Planet: Orbits a star, nearly spherical.
• Satellite: Object orbiting a planet.
• Life Cycle of Stars: From nebula to main sequence, to red giant/supernova.
• Big Bang Theory Evidence: Redshift and cosmic microwave background radiation (CMBR).

Conclusion

• Prepare with confidence; you are ready for your IGCSE Physics Paper 4.
• Best of luck in the examination!