Carbon-14 has a half-life of 5730 years. If an original sample was 100g of C¹4 and it is now 0.781g of C14, how old is your sample?

Respuesta :

Answer:

40,113 years

Explanation:

To find the age of the sample, you need to use the half-life formula:

[tex]N(t)=N_0(\frac{1}{2})^{t/h[/tex]

In this formula:

------> N(t) = current mass (g)

------> N₀ = initial mass (g)

------> t = time passed (yrs)

------> h = half-life (yrs)

You can plug the given values into the equation and rearrange the formula to find "t".

N(t) = 0.781 g                       t = ? yrs

N₀ = 100 g                           h = 5730 yrs

[tex]N(t)=N_0(\frac{1}{2})^{t/h[/tex]                                           <----- Half-life formula

[tex]0.781=100(\frac{1}{2})^{t/5730}[/tex]                                     <----- Insert values

[tex]0.00781=(\frac{1}{2})^{t/5730}[/tex]                                       <----- Divide both sides by 100

[tex]log_{1/2}(0.00781)=log_{1/2}((\frac{1}{2})^ {t/5730})[/tex]               <----- Take [tex]log_{1/2}[/tex] of both sides

[tex]7.00 = \frac{t}{5730}[/tex]                                                   <----- Solve [tex]log_{1/2}[/tex]

[tex]40,113 = t[/tex]                                                   <----- Multiply both sides by 5730

The given sample is 40,113 years .

What do you mean by half-life ?

Half-life, in radioactivity, is the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay.

Half-life formula,

[tex]\rm N(t)\;=N_0(\dfrac{1}{2})^\frac{t}{t1/2}[/tex]   .......(1)

where,

N(t)=current mass

N₀=initial mass

t=time period

h=half -life

Given,

N(t)=0.781g, t=? yrs, N₀=100g, h=5730 years

[tex]\rm N(t)\;=N_0(\dfrac{1}{2})^\frac{t}{t1/2}[/tex]

put the values, in ......(1)

0.781=100(1/2) [tex]t/5730\\[/tex]

log₁/₂(0.00781)=log₁/₂ ( 1/2)[tex]t/5730[/tex]

7=t/5730

40,113=t

Hence, the given sample is 40,113 years .

Learn more about half-life ,here:

https://brainly.com/question/16387602

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