## University Physics with Modern Physics (14th Edition)

First find the energy density, which depends on the strength of the magnetic field. $$u=\frac{B^2}{2\mu_0 }$$ $$u=\frac{(4.80T)^2}{2(4\pi \times10^{-7}Wb/m \cdot A)}=9.167\times10^6 J/m^3$$ The energy is the energy density, multiplied by the volume. $$U=u(V)=( 9.167\times10^6 J/m^3)(10.0\times10^{-6}m^3)=91.7J$$