AQA GCSE Physics Paper 1 - Key Topics and Concepts

General Overview

• Covers Energy, Electricity, Particles, and Atomic Structure (referred to as Nuclear Physics).
• Relevant for combined Trilogy and separate physics (Topics 1-4).
• Triple Physics has some additional content not relevant for the other tiers.

Energy

• Conservation of Energy: Total energy in a system is conserved; energy cannot be created or destroyed, only transformed.
  • Exception: Energy can convert to mass, relevant in nuclear fission and fusion.
• Energy Stores: Kinetic, Gravitational Potential (GPE), Elastic Potential, Thermal, and Chemical Potential.
  • Kinetic Energy: E = 1/2 mv²
  • Gravitational Potential Energy: E = mgh
  • Elastic Potential Energy: E = 1/2 k e²
  • Thermal Energy: ΔE = mcΔT (specific heat capacity)

Energy Transfer and Systems

• Energy must be transferred between objects or stores within a closed system.
• Equating energy stores: GPE lost equals kinetic energy gained (e.g., in a roller coaster).

Power and Efficiency

• Power: Rate of energy transfer, P = E/t (Watts = Joules/second).
• Efficiency: Useful energy output/total energy input, can be expressed as a decimal or percentage.

Electricity

• Flow of charge (electrons) through a circuit which transforms energy.
• Basic Circuit Components: Cells, batteries, wires, lamps.
• Current: I = Q/t (Charge flow rate).
• Voltage (Potential Difference): V = E/Q, measured with a voltmeter.
• Resistance: Ohm’s Law V = I × R.

Circuit Design

• Series Circuits: Total voltage is shared, current is the same, total resistance is the sum.
• Parallel Circuits: Voltage is the same across branches, current is divided, adding resistors decreases total resistance.
• Diode and LED: Allow current in one direction, used in controlled light emission.

National Grid and Safety

• AC vs DC: Alternating current for mains, direct current from batteries.
• National Grid: Transmits electricity efficiently by stepping up/down voltage using transformers.
• Household Wiring and Safety: Live wire (brown), Neutral wire (blue), Earth wire (green/yellow).

Particles and Atomic Structure

• Density: ρ = m/V, important for understanding mass distribution.
• States of Matter: Solid, liquid, gas; transitions require energy input.
• Atomic Model Evolution: From plum pudding to nuclear model.

Radioactivity and Nuclear Physics

• Types of radiation: Alpha, Beta, Gamma.
• Half-life: Time for half of the radioactive isotopes to decay, important for understanding radioactive decay processes.
• Nuclear Fission and Fusion:
  • Fission: Splitting of heavy nuclei into lighter ones, releases energy.
  • Fusion: Combining light nuclei to form heavier ones, also releases energy, but difficult to achieve on Earth.

This summary captures the main points discussed in the lecture, focusing on the essential equations, concepts, and practical applications needed for understanding AQA GCSE Physics Paper 1 topics.