P7 Flashcards
What does a radioactive substance contain
An unstable nuclei that becomes stable by emmitting radiation
What are the three types of nuclear radiation emmited
Alpha radiation, beta radiation and gamma radiation
Whar is radioactive decay
A random event you cannot predict when it will happen
Whatr did rutherford do
Used a paricles to probe inside an atom to see that some of the particles were scattered through large angles
What does an atom have
A small positively charges central nucleas where most of the mass of the atom is located
What are isotopse of an element
Are atoms with the same number of protons but different number of neutrons.
Description of alpha radiation
It can be stopped by paper and has a range of a few cm in the air and conists of particles with two protons and two neutrons
How is beta radiation stopped
By a thin sheet of metal and has a range of about one meter in air
Description of beta radiations and particles
It consist of fast moving electrons emitted from the nucleas
-it is less ionising than alpha particles but more ionising than gamma
How is gamma radiation stopped
By a thick lead and has an unlimited range in the air
What does gamma particles consist of
Electromagnetic radiation
What is the half life of a radioactive isotope
The average time it takes for the number of nuclei of te isotopes in a samples to halve
What is the count rate of a geiger counter caused by
A radioactive source decreased as the activity of the source decreases
What decreases by half every half-life
The number of atoms of a radioactive isotope and the count rate
