A sample of Iron-59 contains 50 mg. One hundred days later, the sample contains 10.75 mg. What is the half-life of iron-59, in days? Round to the nearest tenth.

Respuesta :

Answer:

[tex]t_{1/2}=45.09 d[/tex]    

Step-by-step explanation:

We can use the decay equation:

[tex]M=M_{0}e^{-\lambda t}[/tex]

  • M(0) is the initial mass
  • M is the mass after t (1000 days) time
  • λ is the decay constant

But:

[tex]\lambda = ln(2)/t_{1/2}[/tex]

  • t(1/2) is the half-life.

So, we can rewrite the initial equation:

[tex]M=M_{0}e^{-\frac{ln(2)}{t_{1/2}}t}[/tex]

Now, we just need to solve it for t(1/2):

[tex]ln(\frac{M}{M_{0}})=-\frac{ln(2)}{t_{1/2}}t[/tex]

[tex]t_{1/2}=-\frac{ln(2)}{ln(\frac{M}{M_{0}})}t[/tex]

[tex]t_{1/2}=-\frac{ln(2)}{ln(\frac{10.75}{50})}100[/tex]                

[tex]t_{1/2}=45.09 d[/tex]    

I hope it helps you!

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