P4 Book Work Flashcards
(27 cards)
What is alpha radiation?
Highly ionising, not very penetrating, helium nuclei, positively charged, stopped in air
What is an atom?
Smallest part of an element
What is atomic mass?
Number of protons and neutrons in an atom nucleus
What is atomic number?
Number of protons in an atom(also electrons)
What is beta radiation?
Quite ionising and penetrating, high speed electron, negatively charged, stopped by thin sheet of aluminium
Contamination definition
When an object has radiation introduced to it, and becomes radioactive for as long as the source
Electron definition
Negative particle of an atom
Gamma radiation defined
Most penetrating radiation, least ionising, not a particle, part of the EM spectrum
Define ionisation
The process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons
Define irradiation
Exposing an object to radiation
Define half-life
The time it takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to half or for the count rate to half
What is an isotope?
Atoms of an element with the same number of protons but a different number of neutrons
What is a neutron?
A neutral particle in the nucleus of an atom
What is radioactive decay?
The process by which an unstable atomic nucleus loses energy by radiation
What is the count rate?
Number of decay is recorded each second by a detector such as the Geiger-Müller tube
What is nuclear fusion?
Nuclear fusion is the joining of two nuclei to form a heavier nucleus
What is nuclear fission?
The process of splitting a large, unstable atomic nucleus into smaller nuclei
Define electron excitation
Energy levels of electrons are not fixed. When electrons absorb energy, they move up energy levels.
What is electron deexcitation?
When electrons lose energy they emit an electromagnetic wave and drop-down energy levels
Define an unstable atom
An atom that has unbalanced forces holding it together. Unstable atoms can decay to form new, more stable atoms
What happens when an alpha particle is emitted from an atom?
Two protons and two neutrons are lost from the nucleus. This means that the mass number drops by four and the atomic number drops by two.
What happens when a beta particle is emitted from an atom?
A neutron turns into a proton this means that the mass number stays the same, but the atomic number increases by one
What is a becquerel
This is the unit of the activity of a radioactive sample or the count rate of the sample. It is the same rate of one count per second.
What are safety precautions when handling radioactive sources?
-Keep exposure times as short as possible
-Monitor exposure with a film dose badge
-Label radioactive sources clearly
-Store radioactive sources in shielded containers
-Wear protective clothing
-Use tongs or a robotic arm to handle radioactive materials
