Alpha, Beta & Gamma Particles Some elements have nuclei that are unstable This tends to be when the number of nucleons does not balance In order to become more stable, they emit particles and/o...
Background Radiation It is important to remember that radiation is a natural phenomenon Radioactive elements have always existed on Earth and in outer space However, human activity has added to the...
Isotopes AZX Notation A nuclide is a group of atoms containing the same number of protons and neutrons For example, 5 atoms of oxygen are all the same nuclide but are 5 separate atoms Atomic symbol...
Emission & Absorption Spectrum Line Spectra Line spectra is a phenomenon that occurs when excited atoms emit light of certain wavelengths which correspond to different colours This comes from d...
Transitions Between Energy Levels Difference in discrete energy levels The difference between two energy levels is equal to a specific photon energy The energy (hf) of the photon is given by: ΔE = ...
Discrete Energy Levels The Photon Model Photons are fundamental particles that make up all forms of electromagnetic radiation A photon is a massless “packet” or a “quantum” of electromagnetic energ...
Gravitational Field Strength There is a universal force of attraction between all matter with mass This force is known as the ‘force due to gravity’ or the weight The Earth’s gravitational field is...
Circular Orbits Since most planets and satellites have a near circular orbit, the gravitational force FG between the sun or another planet provides the centripetal force needed to stay in an orbit ...
Newton's Law of Gravitation The gravitational force between two bodies outside a uniform field, e.g. between the Earth and the Sun, is defined by Newton’s Law of Gravitation Recall that the mass of...
