topic 4 - atomic structure Flashcards
where does background radiation come from?
- natural sources such as rocks and cosmic rays from space
- man-made sources such as the fallout from nuclear weapons testing and nuclear accidents
how should be background radiation be dealt with in calculations?
the background count should be subtracted from any readings before calculations are attempted
what is a possible risk to health caused by using a radioactive source?
can cause cancer or can damage cells
what factor determines how dangerous a particular radioactive isotope is?
the half-life of the isotope
What are two uses of nuclear radiation in medicine?
- an exploration of internal organs
- control or destruction of unwanted tissue
how is radiation used in sterilisation?
Gamma emitters are used to kill bacteria/parasites on equipment
explain the process of radiotherapy
- gamma emitters direct gamma rays at cancerous cells
- the cancerous cells absorb the radiation and are killed
what is nuclear fission?
the splitting of a large and unstable nucleus
describe the process of nuclear fission
- a uranium nucleus absorbs a slow-moving neutron.
- The nucleus splits into two smaller nuclei and emits two or three neutrons and gamma rays
how is a chain reaction controlled when a neutron starts it?
it is controlled in a nuclear reactor which controls energy released
what is nuclear fusion?
the joining of two light nuclei to form heavier nuclei. some of the mass of the nuclei is converted to energy
what is an example of a fissionable isotope
Uranium - 235
why is nuclear fusion currently not a viable way to produce energy on Earth?
with current equipment/techniques, the energy required is greater than energy released, resulting in a net energy loss
