A long bar of rectangular cross section of $0\mathrm{.}12m0\mathrm{.}15m,$ and having a thermal conductivity of $1\mathrm{.}5\frac{W}{m}K,$ is

subjected to the boundary conditions shown. Using an appropriate numerical technique with a grid of $x=y=$

$0\mathrm{.}03m,$ determine the Finite$-$Different Equation of each nodes.