Question

A medical scientist has a 15-gram sample of I-13, And would like to know it's half-life in days. he also knows that k=0.0856

Answer 1

Answer:

8.1

Step-by-step explanation:

Answer 2

Answer:

The number of days is approximately 8.                    

Step-by-step explanation:

Given : A medical scientist has a 15-gram sample of I-13, And would like to know it's half-life in days. he also knows that k=0.0856.

To find : The half-life, in days, of I-131 using the information at the left?

Solution :

The decay model is given by  $N=N_0e^{-Kt}$

We have given that,  

The substance's half-life is the time it takes for the substance to decay to half its original amount.

i.e. $N=\frac{N_0}{2}$

The value of k is k=0.0856.

Substitute the values in the formula,

 $N=N_0e^{-Kt}$

 $\frac{N_0}{2}=N_0e^{-(0.0856)t}$

 $\frac{1}{2}=e^{-(0.0856)t}$

Taking natural log both side,

 $\ln\frac{1}{2}=\ln e^{-(0.0856)t}$

 $-\ln2=-(0.0856)t\ln e$

 $t=\frac{-\ln2}{-0.0856}$

 $t=8.09$

Therefore, The number of days is approximately 8.