Answer
$ E=6.28\times 10^{10}\frac{V}{m}$
Work Step by Step
We know that
$\frac{1}{2}\epsilon_{\circ}E^2=\frac{Energy}{Volume}$
$\implies E^2=\frac{2Energy}{Volume\times \epsilon_{\circ}}$
We plug in the known values to obtain:
$E^2=\frac{2\times 17.5}{10^{-9}\times 8.85\times 10^{-12}}$
$E^2=3.95\times 10^{21}$
$\implies E=6.28\times 10^{10}\frac{V}{m}$
