Question

Cobalt-60 has a half-life of about 5 years. After 20 years, how many grams of a2,076 gram sample will remain? Round to the hundredths place, if answer doesn'thave a tenths place then use a zero so the answer does.

Answer 1

The formula for half-life is given below as

`N(t)=N_0((1)/(2))^{(t)/((t1)/(2))}`

Where the given values are

`\begin{gathered} N_0=2076g \\ t=20years \\ t^{(1)/(2)}=5years \end{gathered}`

By substituting the values, we will have

`\begin{gathered} N(t)=N_(0)((1)/(2))^{(t)/((t*1)/(2))} \\ N(t)=2076*((1)/(2))^{(20)/(5)} \\ N(t)=2076*((1)/(2))^4 \\ N(t)=(2076)/(16) \\ N(t)=129.75g \end{gathered}`

Hence,

The final answer is

`\Rightarrow129.75g`