contestada

You are dating Moon rocks based on their proportions of uranium-238 (half-life of about 4.5 billion years) and its ultimate decay product, lead.

1. Find the age for a rock for which you determine that 55% of the original uranium-238 remains, while the other 45% has decayed into lead.

2. Find the age for a rock for which you determine that 68% of the original uranium-238 remains, while the other 32% has decayed into lead.

Respuesta :

akiyama316
1. Use the formula:

[tex]-kt = ln[\frac{FinalAmount}{InitialAmount}][/tex]

[tex]k = ln2 / half-life[/tex]

So, [tex]t = - \frac{4.5}{ln2} \times ln[\frac{0.55}{1}][/tex]

t =  3.8 billion yr

2.  Same formula:

[tex]t = - \frac{4.5}{ln2} \times ln[\frac{0.63}{1}][/tex]

t = 2.93 billion yr.

Otras preguntas