Half-Life (AQA GCSE Physics): Flashcards
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13 cards from this deck
Definition of half-life
Definition of half-life
Time for half the nuclei to decay OR activity/count rate to halve
Is half-life constant or variable?
Is half-life constant or variable?
Constant
Half-life if 80 atoms→20 in 10 min?
Half-life if 80 atoms→20 in 10 min?
5 min (2 half-lives)
Short half-life characteristic?
Short half-life characteristic?
Very radioactive initially, quickly dies down
Which half-life has less long-term risk?
Which half-life has less long-term risk?
Short half-life
Long half-life characteristic?
Long half-life characteristic?
Weakly radioactive for long period
Americium half-life?
Americium half-life?
432 years
Americium use?
Americium use?
Smoke alarms (alpha emitter)
Count rate definition?
Count rate definition?
Radiation counts reaching detector per second
Activity unit & meaning?
Activity unit & meaning?
Bq (Becquerel): Bq decay/second
Does activity reach zero?
Does activity reach zero?
No, never reaches zero
Device measuring radiation count rate?
Device measuring radiation count rate?
Geiger-Muller tube (and counter)
Nature of radioactive decay?
Nature of radioactive decay?
Random & unpredictable