The count rate of a radioactive source decreases from 1600 counts per minute to 400 counts per minute in 12 hours. What is the half-life of the source?

Respuesta :

Answer:

[tex]t_{1/2}=6 h[/tex]

Explanation:

Let's use the decay equation.

[tex]A=A_{0}e^{-\lambda t}[/tex]

Where:

  • A is the activity at t time
  • A₀ is the initial activity
  • λ is the decay constant

We know that [tex]\lambda=\frac{ln(2)}{t_{1/2}}[/tex]

So we have:

[tex]\lambda=\frac{ln(A/A_{0})}{t}[/tex]

[tex]\frac{ln(2)}{t_{1/2}}=\frac{ln(A/A_{0})}{t}[/tex]

[tex]t_{1/2}=\frac{t*ln(2)}{ln(A/A_{0})}[/tex]

[tex]t_{1/2}=6 h[/tex]

Therefore, the half-life of the source is 6 hours.

I hope it helps you!