Radiation Flashcards
DESCRIBE THE MODEL OF AN ATOM
- In an uncharged atom, the number of protons in the nucleus are even to the number of electrons orbiting the nucleus.
- The nucleus contains protons and neutrons.
- Electrons, negative.
Protons, positive
Neutrons, neutral
DESCRIBE ALPHA RADIATION
An alpha particle is a helium nucleus (two protons and two neutrons) with a positive charge. It is large in size compared to beta.
DESCRIBE BETA RADIATION
A beta particle is a high speed electron (produces within the nucleus) and is negative. It is small compared to alpha.
DESCRIBE GAMMA RADIATION
Gamma radiation is a high frequency, high energy electromagnetic wave. It travels at the speed of light.
HOW DOES A RADIOACTIVE MATERIAL BECOME STABLE
A radioactive material is made up of atoms with unstable nuclei. They become stable when the nucleus decays and emits alpha, beta or gamma.
DESCRIBE IONISATION
Ionisation is when an electron is added to an atom or lost from an atom making it charged. What is left is called an ion. Alpha is most ionising and gamma is least ionising.
HOW DOES RADIATION KILL LIVING CELLS
When living tissue receives a dose of radiation, ionisation takes place which can disrupt the way the cells operate.
HOW DOES A GEIGER MULLER TUBE WORK
The tube detects gas. The ions in the gas produce a current in the tube for a short time. This current produces voltage pulses and the voltage pulses are measured on the counter.
WHAT IS EACH RADIATION ABSORBED BY
- Alpha radiation is absorbed by a piece of paper or a few cm of air
- Beta is absorbed by a few mm of aluminium or a few m of air.
- Gamma is absorbed by a few cm of lead or a few km of air.
WHAT IS ACTIVITY
The number of radioactive decays per second (Bequerells)
WHAT IS BACKGROUND RADIATION
Background radiation is radiation from our surroundings and is normally at a low level.
WHAT ARE NATURAL SOURCES OF RADIATION
Radon gas from rocks, Gamma rays from the ground, Cosmic rays from space.
WHAT ARE ARTIFICIAL SOURCES OF RADIATION
Medical applications such as tracers, fallout from weapon testing, nuclear waste from power stations.
MEDICAL APPLICATIONS OF RADIATION
Radiotherapy, x-rays, tracers
INDUSTRIAL APPLICATIONS
Testing welds