P4 Combined Flashcards
1
Q
What is contamination?
A
When there is direct contact with a radioactive substance
2
Q
What is irradiation?
A
When an object is exposed to radiation
3
Q
What is ‘half-life’ ?
A
The time it takes for the number of radioactive nuclei to fall by half
4
Q
What is Alpha radiation?
A
Helium nucleus with two protons and two neutrons. Mass 4 and charge is +2 and is blocked by paper
5
Q
What is beta radiation?
A
High energy electron, stopped by a few mm of aluminium
6
Q
What is gamma radiation?
A
Em wave, least ionising, stopped by several cm of lead
7
Q
What is a positive ion and a negative ion?
A
Positive ions mean that the atom has lost an electron ( or electrons )
Negative ions mean that the atom has gained an electron ( or electrons )
