P4 - Radioactivity Flashcards
What does an alpha particle contain?
2 neutrons + 2 protons
What safety procedures must be followed with working with something radioactive?
Don't handle directly Never point a source Store in lead lined containers Wear protection suits Wear a radiation badge
What electric charge does an alpha particle have?
+2
What is the relative atomic mass of an alpha particle?
4
Where is alpha radiation the most dangerous and why?
It is most dangerous inside the body because it cannot escape out of the skin
What happens to an alpha particle in a magnetic field?
It is weakly affected
What is a beta particle?
A high energy electron
What is the electric charge of a beta particle?
-1
What is the relative mass of a beta particle?
1/1860th (very small)
What is the effect of a magnetic field on a beta particle?
It is strongly affected
What is gamma?
High energy electromagnetic radiation
What charge does a gamma ray have?
No charge
Where is gamma the most dangerous?
Outside the body
What stops alpha?
Skin or paper
What stops beta?
Thin aluminium
What stops gamma?
Thick lead REDUCES gamma
How can you dispose of nuclear waste?
Store in strong security in the station
Dump it far out into sea
Store in deep non-permeable rock
What is another name for the alpha particle?
Helium nuclei
Describe alpha decay?
2 neutrons and 2 protons are emitted from the nucleus
Describe the effects of alpha decay
Mass number decreases by 4, atomic number decreases by 2
Describe beta radiation
A neutron in the nucleus decays into a proton and a high energy electron is emitted
What is the effect of beta decay
Mass stays the same, atomic number increased by one
Describe gamma decay
Nucleus changes shape into a more stable one. Gamma radiation is emitted
What is the effect of gamma decay?
It all stays the same
What are the two definitions of half life?
The time it takes for count rate to decrease by 50%
Time taken for number of radioactive nuclei in a sample to decrease by 50%
How to do you work out a half life?
Map out each half and put the numbers with it e.g
12—->24—->36—->48
1/2—>1/4—>1/8—>1/16
