Modelling Decay Flashcards
What is radioactive decay?
When unstable nuclei break down until they reach a stable form
What can be said about how raidoactive decay occurs?
It is random-so cant tell when a nucleus will decay and which nucleus will decau
What is activity?
Number of unstable nuclei that decay each second
What is activity proportional to?
- Size of sample
- so activity decreases as nuclei decay as less undecayed nuclei remain
What can radioactivity be modelled by?
Exponential decay curve
if theyres a very large number of undecayed nuclei
What is the decay constant?
Probability of a given nucleus decaying in a certain time
Bigger decay constant faster the rate of decay
Symbol lambda
Equation for acitivity?
A=N lambda
(N is number if undecayed nuclei)
Lambda is decay constant)
Unit of activity
Bq (becquerrels)
What is rate of decay proportional to?
Number of undecayed nuclei remaining
What is the half life of an isotope?
Average time for number of undecayed nuclei to halve in value
How to experimentally make a decay graph?
- Use a protactinium generator
- initilally has seperated layers because fully decayed
- Take background count rate that comes form backgroundradation
- shake bottle and wait for liquids to sperate-as soon as they do record count rate and fixed time intervals
- Subtract backround count from measure ocunt rates then plot count rate over time
What is capacitance?
Amount of charge stored per volt
What is a capacitor?
Two metal plates seperated by an insulator
They store electrical charge
What is capacitance unit?
Farads
