Half-Life (OCR GCSE Physics A, Combined (Gateway Science Suite)): Flashcards
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Half-life definition (nuclei)
Half-life definition (nuclei)
Time for half the nuclei in a sample to decay
Half-life definition (activity)
Half-life definition (activity)
Time for activity/count rate to fall by half
Is half-life constant or variable?
Is half-life constant or variable?
Constant
Short half-life: initial radioactivity?
Short half-life: initial radioactivity?
Very radioactive
Long half-life characteristic?
Long half-life characteristic?
Weakly radioactive for long period
Half-life of Americium?
Half-life of Americium?
432 years
Use of Americium?
Use of Americium?
Smoke alarms
Type of radiation emitted by Americium?
Type of radiation emitted by Americium?
Alpha
Why is Americium suitable for smoke alarms?
Why is Americium suitable for smoke alarms?
Won't need replenishing, weak activity, not harmful
Count rate definition
Count rate definition
Number of radiation counts per second
Activity (Bq) definition
Activity (Bq) definition
Rate at which a source decays
What does 1 Bq equal?
What does 1 Bq equal?
1 decay per second
Does activity ever reach zero?
Does activity ever reach zero?
No, never reaches zero
Nature of radioactive decay?
Nature of radioactive decay?
Random and unpredictable
Instrument measuring radiation count rate?
Instrument measuring radiation count rate?
Geiger-Muller tube and counter