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A radioactive substance has half-life T1/2 = 5 years — JEE Physics

JJulienMoreau51 Asked 2mo ago 924 views 1 answer

A radioactive substance has half-life $T_{1/2} = 5$ years. Find the fraction of material remaining after 20 years.

1 Answer

VAVidaara Admin ✓ Vidaara Team ✓ Accepted · 2mo ago ▲ 19

Number of half-lives: $n = \dfrac{20}{5} = 4$

$$\frac{N}{N_0} = \left(\frac{1}{2}\right)^4 = \frac{1}{16}$$

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Discussion (2)

E
What changes if the medium/conditions were different?
EthanWalker47 · 2mo ago
KS
Brilliant explanation, the substitution step is what I kept missing.
Karan Singh · 2mo ago
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