the half life of sodium-24 is 14.9h. suppose a hospital buys a 40mg sample of sodium-24. a.) how much of the sample will remain after 48h? b.) how long will it be until only 1mg remains?
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First solve for $\displaystyle A$ . $\displaystyle Q = Q_0 \times A^t$ where $\displaystyle t$ is in hours. So we have $\displaystyle 20 = 40 \times A^{14.9}$
how i do it if i were to put in logs into that equation and put it in my calculator?
You do need to use logs here. $\displaystyle 20 = 40 \times A^{14.9}$ $\displaystyle \frac{1}{2} = \times A^{14.9}$ From here apply $\displaystyle a= b^c \implies c=\log_ba$
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