#### Answer

$2.8 \times 10^{14}$

#### Work Step by Step

Consider the exponential growth equation as follows: $y=y_0e^{kt}$
As we are given that $y=2$ and $t=0.5$; $y_0=1$
When we have $ t = 1 hour$
Then $2=e^{0.5k} \implies \ln 2=(0.5) k$
or, $k=\dfrac{\ln 2}{0.5}=\ln 4$
Next, at the end of the $24$ hrs, we get
$y =e^{24 \ln 4} $
Thus, $y=4^{24} =2.8 \times 10^{14}$