AQA AS Level Physics Overview

Classification of Particles

• Hadrons and Leptons: Fundamental groups of particles.
  • Leptons: Fundamental particles (e.g., electron, muon, neutrinos).
    • Electron and muon neutrinos have separate lepton numbers.
  • Hadrons: Not fundamental, composed of quarks.
    • Barons: Made of three quarks.
    • Mesons: Made of a quark-antiquark pair.

Quarks

• Flavors: Up, Down, Strange.
  • Charges: Up (+2/3), Down & Strange (-1/3).
  • Strange Quark: Strangeness -1, Antistrange +1.

Interaction and Forces

• Electromagnetic Force: Affects charged particles, exchange particle is the photon.
• Gravity: Exchange particle is the graviton.
• Weak Nuclear Force: Affects all particles, exchange particles are W+, W-, Z0 bosons.
• Strong Nuclear Force: Only affects hadrons, exchange particles are the gluons.

Conservation Laws

• Charge, baryon number, and lepton numbers must be conserved in interactions.
• Beta Decay: Neutron decays to a proton in beta- decay, electron capture involves W bosons.

Strangeness

• Conserved in strong interactions, changes in weak interactions.

Charge to Mass Ratio

• Calculated as charge in coulombs divided by mass in kg.

Radiation

• Types: Electromagnetic spectrum (emitted by electrons), Gamma (emitted by nucleus).
• Alpha Decay: Emission of two protons and two neutrons.
• Beta Decay: Neutron turns into a proton and emits an electron.

Pair Production and Annihilation

• Photon converts into particles (pair production), particles annihilate into energy.

Energy Levels in Atoms

• Electrons in discrete energy levels; can be excited and ionized.
• Photon emission during de-excitation.
• Energy levels given in Joules or electron volts.

Spectra

• Emission Spectrum: Wavelengths of photons emitted.
• Absorption Spectrum: Wavelengths absorbed by gas or plasma.

Electromagnetic Spectrum

• Ionizing Radiation: High energy, can cause damage, and used in medical applications.

Quantum Mechanics Concepts

• Photoelectric Effect: Evidence of particle nature of light.
• Wave-Particle Duality: Particles exhibit both wave and particle properties.
• De Broglie Wavelength: Wavelength of a moving particle.

Electricity

• Current: Flow of charge.
• Potential Difference (Voltage): Energy per coulomb transferred.
• Ohm’s Law: V = IR.
• Series and Parallel Circuits: Rules for current, voltage, and resistance.

Components

• Resistors: Provide resistance, convert energy to heat.
• Diodes and LEDs: Allow current in one direction, emit light.

Superconductors

• Zero resistance at critical temperature.

Waves

• Longitudinal and Transverse Waves: Types of waves based on particle displacement.
• Refraction and Reflection: Change in speed and direction, total internal reflection.

Optics

• Lenses and Mirrors: Focus and disperse light.
• Optical Fibers: Use of TIR for data transmission.

Mechanics

• Newton's Laws: Motion laws describing forces and reactions.
• Momentum: Product of mass and velocity, conserved in isolated systems.
• Collisions: Elastic and inelastic collisions, momentum conservation.

Experimental Techniques

• Uncertainty and Error: Measurement accuracy, resolution, and systematic/random errors.
• Graphing and Data Analysis: Plotting, log graphs, and interpreting experimental data.

Practical Circuitry

• Internal Resistance and EMF: Calculation and effects on circuits.

Harmonics and Standing Waves

• Stationary Waves: Nodes and antinodes, harmonics on strings and in tubes.

Material Properties

• Elasticity and Deformation: Hooke's law, Young's modulus, stress and strain.

Miscellaneous

• Dimensional Analysis: Checking equations for dimensional consistency.

Important Formulae

• V = IR (Ohm's Law)
• λ = h / mv (De Broglie Wavelength)
• F = ma (Newton’s Second Law)
• E = hf (Energy of a Photon)

These notes cover the fundamental concepts and principles that are critical for understanding AQA AS Level Physics, summarizing the vast range of topics in particle physics, quantum mechanics, electromagnetism, and mechanics.