Answer
The energy stored in a cubic meter is $1.0\times10^{-7}J$
Work Step by Step
Find the energy density using equation 17–11.
Energy density = $\frac{1}{2}\epsilon_o E^2$
$$=\frac{1}{2}(8.85\times10^{-12}C^2/(N\cdot m^2)) (150V/m)^2$$
$$=1.0\times10^{-7}\frac{J}{m^3}$$
That is the energy density, so the energy stored in a cubic meter is $1.0\times10^{-7}J$.
