IB Physics Topic 5 Definitions
This page contains our IB Physics definitions for topic 5. By learning each one of these definitions, you will fully cover the content for IB Physics 'Nuclear & Quantum Physics'.
absorption spectrum
It is the wavelengths of electromagnetic waves an atom can absorb
Antiparticles
This particle has the same mass as a normal particle but opposite charge and quantum number
Background radiation
It is the daily radiation one can be exposed to
Binding energy per nucleon
It is the ratio of nuclear binding energy to number of nucleons in a nucleus
Chandrasekhar Limit
The maximum mass of a white dwarf star (approximately 1.4 solar masses), beyond which it will collapse into a neutron star or black hole
Conditioning
The final step in nuclear waste management, involving encapsulating or solidifying waste in materials like cement, bitumen, or glass, and storing it in corrosion-resistant containers
Control Rods
Retractable rods that absorb neutrons to control the rate of the nuclear chain reaction
Emission spectrum
It is the wavelengths of electromagnetic waves an atom emits
Exchange particle
It is a particles that mediates a fundamental force
Fission
It is the splitting of a large nucleus into two smaller nuclei, releasing energy
Formation of an absorption spectrum
It is formed from the absorption of electromagnetic waves by electrons to jump to a higher energy level
Fusion
It is the joining of two nuclei to form a larger nucleus, releasing energy
Half-life
It is the amount of time for half of the atoms to decay
Hydrostatic Equilibrium
A balance between the outward radiation pressure from fusion reactions and the inward gravitational pull of the gases in a star
Ionizing radiation
It is radiation that it removes electrons from exposed matter
Ions
These are nuclides that have lost or gained electrons, gaining a positive or negative charge
Isotopes
These are nuclides with different numbers of neutrons, and thus different mass numbers
Jeans Criterion
A criterion determining when a cloud of gas will collapse to form a star, dependent on the mass, temperature, and density of the cloud
Mass defect
It is the difference in the mass of a nucleus and the sum of its constituent masses
Moderator
A material within the reactor that slows down neutrons to optimize their speed for successful nuclear reactions
Neutron Bombardment
The process of bombarding fuel rods with neutrons to initiate a fission reaction
Nuclear binding energy
It is the energy released by the production of a nucleus from its constituent nucleons
Nucleon
It is a particle in the nucleus
Nuclides
These are atoms of one element
Photoelectric effect
It is the emission of electrons from a metal surface when UV light shines on it
Quantum tunnelling
It is a particle's ability to escape its potential barrier without sufficient energy
Radiation
It is the emission of electromagnetic waves from an atom by electrons
Radioactive decay
It is the process of decomposition of unstable nuclei into lighter nuclei and emission of radiation
Radioactivity
It is the number of decays occurring per second
Rutherford scattering
It is the prediction of the intensity of alpha particles from the angle of scattering at low energies
Stable orbit
It is an orbit whereing the angular momentum is a multiple of h/2π
Stopping potential
It is the voltage at which there is no electron emission
Supernova
A powerful explosion that occurs when a massive star exhausts its nuclear fuel and its core collapses
Threshold frequency
It is the frequency of absorbed photon below which no electron is emitted
Unified atomic mass unit
It is defined as one twelfth the mass of a Carbon-12 atom
Wave-particle duality
It is the property of sometimes behaving as a wave and sometimes behaving as a particle
Work function
It is the minimum energy that electrons need to escape the metal surface
Next Up
You have completed the topic 5 definitions for IB Physics - continue with related resources below or explore the full IB Physics course from the IBO.
Other topic 5 resources