Physics is the branch of science concerned with substance, energy and the interactions between them.
Many apparently unrelated and complicated phenomena in nature can be understood by relatively simple mathematical concepts. Physicists attempt to uncover these relationships by observing, doing experiments, and creating mathematical models.

THE COURSE AND SYLLABUS

The Leaving Certificate course is divided into several broad topics: Mechanics, Light, Waves, Vibrations and Sounds, Temperature and Heat, Electricity and Magnetism, Modern Physics.
Option 1: Particle Physics 
Option 2: Applied Electricity

Questions in the exam often link across these topics, so it is advisable to study the entire course.

Here below is the syllabus we follow:

Mechanics:

Definitions, Vectors and Scalars, Velocity and Acceleration, Force and Momentum, Moments and Equilibrium, Work, Energy and Power, Density and Pressure, Circular Motion, Gravity, Simple Harmonic Motion, Mechanics Experiments

Temperature and Heat:

Definitions, Temperature Scales, Thermometric Properties, Heat capacity, Heat Transfer, Latent Heat, Heat Experiments

Light: Reflection and Refraction:

Definitions, Reflection, Mirrors, Refraction, Lenses, Lights, Light Experiments

Wave Motion:

Definitions, Properties of Waves, Wave Types, Wave Phenomena, Doppler Effect

Wave Nature of Light:

Definition, Diffraction and interference, Transverse Wave Motion, Colour, Dispersion, Electromagnetic Spectrum, The Spectrometer, Experiments

Vibrations and Sound:

Definitions, Wave Nature of Sound, Resonance, Vibration in Strings and Pipes, Sound Intensity, Sound Experiments

Electrostatics and Capacitance:

Definitions, Charge, Electric Fields, Potential and Capacitance

Current Electricity:

Definitions, Electric current, Voltage, Resistance, Potential Divider Circuit, Effects of Electric Current,
Domestic Circuits, Conduction in Materials, Semiconductors, Electricity Experiments

Electromagnetism:

Definitions, Magnets and Magnetic Fields, Current in a Magnetic Field, Electromagnetic Induction,
Mutual Induction, Self-Induction

Modern Physics:

Definitions, The Electron, Thermionic Emission, The Photoelectric Effect,  X-Rays, Structure of the Atom, Radioactivity, Fission and Fusion

Particle Physics:

Definitions, Mass/Energy Conservation, Cockcroft and Walton Experiment, Conversion Mass to Energy, Converting Energy to Mass, Fundamental Forces, Families of Particles, Quark Model