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Isotope:
Radon-220 · 56 s
Iodine-131 · 8 days
Carbon-14 · 5,730 years
Unstable (not decayed yet)
Decayed (now stable)
Start
New sample
Number left vs time
Time
Half-lives
Still unstable
Expected
Used for
What stops radiation?
Radiation:
Alpha α
Beta β
Gamma γ
Barrier:
Paper
Aluminum (3 mm)
Lead (several cm)