Particles and Waves - Definitions Flashcards
(26 cards)
Electric Field
A Region of space around a charge where another charge will experience a force .
Voltage
- The energy given to each coulomb of charge that passes through a power supply.
- The energy (work done) required to move 1 coulomb of charge in an electric field.
Standard Model
- A model used for classifying (i.e. sorting) fundamental particles and their interactions
Fundamental particles
A particle that is not made up from any other particles, it is in it’s simplest form.
Beta decay
A type of radioactive decay in which a beta particle (electron) is emitted from the nucleus of an atom.
Composite Particle
- A particle that is made up of other particles, it is not a fundamental particle
Hadron
A composite particle that is made up of quarks
- There are two types: Baryons and Mesons
Baryon
A type of hadron that consists of 3 quarks ( e.g. a proton or neutron)
- They are stable particles
Meson
A type of hadron that consists of 2 quarks in a quark-antiquark pair ( e.g. a pion)
- They are unstable and have a short lifetime
Radioactive decay
When unstable nuclei emit nuclear radiation in the form of an alpha particle, beta particle or gamma ray in an attempt to become more stable.
Nuclear fission
The process in which as unstable, heavy atomic nucleus splits into two or more lighter nuclei ( called fission fragments), with energy being released.
Nuclear fusion
The process of small nuclei joining together to form a larger nucleus with energy being released.
Plasma containment
The use of powerful magnetic fields to prevent the high-temperature plasma from physically touching and therefore melting any parts of the reactor.
Irradiance
The power per unit area of electromagnetic radiation incident on a surface.
Photoelectric effect
- Photoelectrons are ejected from the surface of a metal when photons of light with sufficient energy are incident on the surface.
- It provides evidence for the particle model of light
Threshold frequency
The minimum frequency of a photon required to cause the emission of phototelectrons from a metal surface.
Work function
The minimum energy of a photon required to cause the emission of photoelectrons from a metal surface.
Rutherford’s Conclusions ( Gold Foil experiment)
- Most of the atom is empty space
- The atom has a tiny nucleus at it’s centre that contains most of the mass of the atom
- The nucleus is positively charged.
Coherence
- When two or more waves have the same frequency, wavelength and speed
- Waves are said to be coherent if they have a constant phase relationship
Interference
- Observed when coherent waves overlap
- It provides evidence for the wave model of light
Constructive Interference
When two waves of equal amplitude meet in phase, they combine to form a wave of twice the amplitude e.g. Crest meets crest, trough meets trough
Destructive interference
When two waves of equal amplitude meet out of phase, they combine to form a wave of zero amplitude e.g. Crest meets trough
Refraction
The change in speed of light as it passes from one medium ( material) to another. ( e.g. from air to glass)
Absolute refractive Index
It is the ratio of the speed of light in a vacuum to the speed of light in the material
