Half-Life (AQA GCSE Physics Combined Science): Flashcards
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Definition of half-life (nuclei)
Definition of half-life (nuclei)
Time for half the nuclei in a sample to decay
Half-life (activity/count rate)
Half-life (activity/count rate)
Time for activity or count rate to halve
Is half-life constant for an isotope?
Is half-life constant for an isotope?
Yes, it is constant
What is the long-term risk of a short half-life source?
What is the long-term risk of a short half-life source?
Less of a long-term risk
What is the initial activity like for a short half-life source?
What is the initial activity like for a short half-life source?
Very radioactive initially, quickly dies down
What is the characteristic of a long half-life source?
What is the characteristic of a long half-life source?
Weakly radioactive for a long period of time
Half-life of Americium
Half-life of Americium
432 years
Use of Americium
Use of Americium
Smoke alarms
Type of radiation from Americium
Type of radiation from Americium
Alpha emitter
Count rate definition
Count rate definition
Number of radiation counts per second
Activity (Bq) definition
Activity (Bq) definition
Rate at which a source decays ()
Nature of radioactive decay process
Nature of radioactive decay process
Completely random process
Instrument to measure radiation
Instrument to measure radiation
Geiger-Muller tube and counter
Does activity ever reach zero?
Does activity ever reach zero?
No, never reaches zero
after 2 half-lives
after 2 half-lives
(25% of initial)