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Compulsory Content

3.1 - Measurements and Their Errors

3.1.1 - Use of SI Units and Their Prefixes

3.1.2 - Limitation of Physical Measurements

3.1.3 - Estimation of Physical Quantities

3.2 - Particles and Radiation / 3.2.1 - Particles

3.2.1.1 - Constituents of the Atom

3.2.1.2 - Stable and Unstable Nuclei

3.2.1.3 - Particles, Antiparticles and Photons

3.2.1.4 - Particle Interactions

3.2.1.5 - Classification of Particles

3.2.1.6 - Quarks and Antiquarks

3.2.1.7 - Applications of Conservation Laws

3.2 - Particles and Radiation / 3.2.2 - Electromagnetic Radiation and Quantum Phenomena

3.2.2.1 - The Photoelectric Effect

3.2.2.2 - Collisions of Electrons with Atoms

3.2.2.3 - Energy Levels and Photon Emission

3.2.2.4 - Wave-Particle Duality

3.3 - Waves / 3.3.1 - Progressive and Stationary Waves

3.3.1.1 - Progressive Waves

3.3.1.2 - Longitudinal and Transverse Waves

3.3.1.3 - Superposition and Stationary Waves

RP01 - Stationary Waves on a String

3.3 - Waves / 3.3.2 - Refraction, Diffraction and Interference

3.3.2.1 - Interference

3.3.2.2 - Diffraction

RP02 - Interference Effects

3.3.2.3 - Refraction at a Plane Surface

3.4 - Mechanics and Materials / 3.4.1 - Force, Energy and Momentum

3.4.1.1 - Scalars and Vectors

3.4.1.2 - Moments

3.4.1.3 - Motion Along a Straight Line

RP03 - Determination of g by Free Fall

3.4.1.4 - Projectile Motion

3.4.1.5 - Newton's Laws of Motion

3.4.1.6 - Momentum

3.4.1.7 - Work, Energy and Power

3.4.1.8 - Conservation of Energy

3.4 - Mechanics and Materials / 3.4.2 - Materials

3.4.2.1 - Bulk Properties of Solids

3.4.2.2 - The Young Modulus

RP04 - Determination of the Young Modulus

3.5 - Electricity / 3.5.1 - Current Electricity

3.5.1.1 - Basics of Electricity

3.5.1.2 - Current-Voltage Characteristics

3.5.1.3 - Resistivity

RP05 - Determination of Wire Resistivity

3.5.1.4 - Circuits

3.5.1.5 - Potential Divider

3.5.1.6 - Electromotive Force and Internal Resistance

RP06 - EMF and Internal Resistance

3.6 - Further Mechanics and Thermal Physics / 3.6.1 - Periodic Motion

3.6.1.1 - Circular Motion

3.6.1.2 - Simple Harmonic Motion

3.6.1.3 - Simple Harmonic Systems

RP07 - Simple Harmonic Motion

3.6.1.4 - Forced Vibrations and Resonance

3.6 - Further Mechanics and Thermal Physics / 3.6.2 - Thermal Physics

3.6.2.1 - Thermal Energy Transfer

3.6.2.2 - Ideal Gases

RP08 - Boyle's Law and Charles's Law

3.6.2.3 - Molecular Kinetic Theory Model

3.7 - Fields and Their Consequences / 3.7.1 - Fields

3.7 - Fields and Their Consequences / 3.7.2 - Gravitational Fields

3.7.2.1 - Newton's Law of Gravitation

3.7.2.2 - Gravitational Field Strength

3.7.2.3 - Gravitational Potential

3.7.2.4 - Orbits of Planets and Satellites

3.7 - Fields and Their Consequences / 3.7.3 - Electric Fields

3.7.3.1 - Coulomb's Law

3.7.3.2 - Electric Field Strength

3.7.3.3 - Electric Potential

3.7 - Fields and Their Consequences / 3.7.4 - Capacitance

3.7.4.1 - Capacitance

3.7.4.2 - Parallel Plate Capacitor

3.7.4.3 - Energy Stored by a Capacitor

3.7.4.4 - Capacitor Charge and Discharge

RP09 - Capacitor Charge and Discharge

3.7 - Fields and Their Consequences / 3.7.5 - Magnetic Fields

3.7.5.1 - Magnetic Flux Density

RP10 - Force on a Current-Carrying Wire

3.7.5.2 - Moving Charges in a Magnetic Field

3.7.5.3 - Magnetic Flux and Flux Linkage

3.7.5.4 - Electromagnetic Induction

RP11 - Magnetic Flux Linkage with a Search Coil

3.7.5.5 - Alternating Currents

3.7.5.6 - The Operation of a Transformer

3.8 - Nuclear Physics / 3.8.1 - Radioactivity and Nuclear Energy

3.8.1.1 - Rutherford Scattering (A-level only)

3.8.1.2 - Alpha, Beta and Gamma Radiation

RP12 - Inverse-Square Law for Gamma Radiation

3.8.1.3 - Radioactive Decay

3.8.1.4 - Nuclear Instability

3.8.1.5 - Nuclear Radius

3.8.1.6 - Mass and Energy

3.8.1.7 - Induced Fission

3.8.1.8 - Safety Aspects

Optional Sections (your school picks one)

3.9 - Astrophysics (Option A) / 3.9.1 - Telescopes

3.9.1.1 - Two-Lens Astronomical Telescopes

3.9.1.2 - Reflecting Telescopes

3.9.1.3 - Radio, Infrared, Ultraviolet and X-ray Telescopes

3.9.1.4 - Telescope Diameter and Detectors

3.9 - Astrophysics (Option A) / 3.9.2 - Classification of Stars

3.9.2.1 - Classification by Luminosity

3.9.2.2 - Absolute Magnitude and Distance

3.9.2.3 - Stellar Temperature and Black-Body Radiation

3.9.2.4 - Stellar Spectral Classes

3.9.2.5 - The Hertzsprung–Russell Diagram

3.9.2.6 - Supernovae, Neutron Stars and Black Holes

3.9 - Astrophysics (Option A) / 3.9.3 - Cosmology

3.9.3.1 - Doppler Effect

3.9.3.2 - Hubble's Law

3.9.3.3 - Quasars

3.9.3.4 - Detection of Exoplanets

3.10 - Medical Physics (Option B) / 3.10.1 - Physics of the Eye

3.10.1.1 - Physics of Vision

3.10.1.2 - Defects of Vision and Their Correction Using Lenses

3.10 - Medical Physics (Option B) / 3.10.2 - Physics of the Ear

3.10.2.1 - Ear as a Sound Detection System

3.10.2.2 - Sensitivity and Frequency Response

3.10.2.3 - Defects of Hearing

3.10 - Medical Physics (Option B) / 3.10.3 - Biological Measurement

3.10.3.1 - Simple ECG Machines and the Normal ECG Waveform

3.10 - Medical Physics (Option B) / 3.10.4 - Non-Ionising Imaging

3.10.4.1 - Ultrasound Imaging

3.10.4.2 - Fibre Optics and Endoscopy

3.10.4.3 - Magnetic Resonance Scanner

3.10 - Medical Physics (Option B) / 3.10.5 - X-Ray Imaging

3.10.5.1 - The Physics of Diagnostic X-rays

3.10.5.2 - Image Detection and Enhancement

3.10.5.3 - Absorption of X-rays

3.10.5.4 - CT Scanner

3.10 - Medical Physics (Option B) / 3.10.6 - Radionuclide Imaging and Therapy

3.10.6.1 - Imaging Techniques

3.10.6.2 - Half-life

3.10.6.3 - Gamma Camera

3.10.6.4 - Use of High-Energy X-rays

3.10.6.5 - Use of Radioactive Implants

3.10.6.6 - Imaging Comparisons

3.11 - Engineering Physics (Option C) / 3.11.1 - Rotational Dynamics

3.11.1.1 - Concept of Moment of Inertia

3.11.1.2 - Rotational Kinetic Energy

3.11.1.3 - Rotational Motion

3.11.1.4 - Torque and Angular Acceleration

3.11.1.5 - Angular Momentum

3.11.1.6 - Work and Power

3.11 - Engineering Physics (Option C) / 3.11.2 - Thermodynamics and Engines

3.11.2.1 - First Law of Thermodynamics

3.11.2.2 - Non-Flow Processes

3.11.2.3 - The p-V Diagram

3.11.2.4 - Engine Cycles

3.11.2.5 - Second Law and Engines

3.11.2.6 - Reversed Heat Engines

3.12 - Turning Points in Physics (Option D) / 3.12.1 - The Discovery of the Electron

3.12.1.1 - Cathode Rays

3.12.1.2 - Thermionic Emission of Electrons

3.12.1.3 - Specific Charge of the Electron

3.12.1.4 - Millikan's Oil-Drop Experiment

3.12 - Turning Points in Physics (Option D) / 3.12.2 - Wave-Particle Duality

3.12.2.1 - Newton and Huygens

3.12.2.2 - Young's double-slit evidence

3.12.2.3 - Electromagnetic waves

3.12.2.4 - The discovery of photoelectricity

3.12.2.5 - Wave–particle duality

3.12.2.6 - Electron microscopes

3.12 - Turning Points in Physics (Option D) / 3.12.3 - Special Relativity

3.12.3.1 - The Michelson-Morley Experiment

3.12.3.2 - Einstein's Theory of Special Relativity

3.12.3.3 - Time Dilation

3.12.3.4 - Length Contraction

3.12.3.5 - Mass and Energy

3.13 - Electronics (Option E) / 3.13.1 - Sensing Devices

3.13.1.1 - MOSFET

3.13.1.2 - Zener diode

3.13.1.3 - Photodiode

3.13.1.4 - Hall effect sensor

3.13 - Electronics (Option E) / 3.13.2 - Signal Processing

3.13.2.1 - Analogue and Digital Signals

3.13 - Electronics (Option E) / 3.13.3 - Filters and Amplifiers

3.13.3.1 - LC Resonance Filters

3.13.3.2 - The Ideal Operational Amplifier

3.13 - Electronics (Option E) / 3.13.4 - Op-Amp Circuits

3.13.4.1 - Inverting Amplifiers

3.13.4.2 - Non-Inverting Amplifiers

3.13.4.3 - Summing and Difference Amplifiers

3.13.4.4 - Real Operational Amplifiers

3.13 - Electronics (Option E) / 3.13.5 - Digital Electronics

3.13.5.1 - Combinational Logic

3.13.5.2 - Sequential Logic

3.13.5.3 - Astables

3.13 - Electronics (Option E) / 3.13.6 - Communication Systems

3.13.6.1 - Principles of Communication Systems

3.13.6.2 - Transmission Media

3.13.6.3 - Time-Division Multiplexing

3.13.6.4 - AM and FM

3.13.6.3 - Time-Division Multiplexing

3.13.6.3 - Time-Division Multiplexing

Time-division multiplexing lets several information streams share one link by taking turns. Follow the slots through a frame, explain how timing preserves their identities, and calculate how the finite capacity is shared.

Sharing a channel in time

Several conversations can share one optical fibre without their data becoming inseparable. Multiplexing combines streams for transmission over a shared channel. In time-division multiplexing (TDM) each stream uses the channel during an allocated interval, then another takes its turn.

In the simple fixed-slot system studied here, the allocation repeats. Only one stream occupies a given data slot; several streams appear to be carried simultaneously to their users because the switching is rapid and data can be buffered and reassembled. TDM organises existing capacity; it does not create bandwidth or increase the speed at which the wave travels.

Frames and reconstruction

The multiplexer selects successive inputs and places a short piece of each on the output. A frame is one complete repeating cycle of slots. For four inputs, a simple sequence is $A_1,B_1,C_1,D_1$ , then $A_2,B_2,C_2,D_2$ : the letter identifies the source and the subscript identifies its next piece, not the binary value being transmitted.

[DIAGRAM: asset_name: E.6.3 - Time-Division Multiplexing - Diagram 1; asset_slug: E.6.3 - Time-Division Multiplexing - Diagram 1; caption: Four inputs interleaved into two successive TDM frames; description: Four inputs interleaved into two successive TDM frames]

At the far end, the demultiplexer routes the first input's slots to output A, the second's to B, and so on. Receiver electronics then rebuild each stream in order. The dashed loop in the schematic means that the allocation repeats; it is not a physical feedback wire. Real frames can also contain synchronisation or control information, so a frame need not consist only of the user-data slots.

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