Unstable chemicals have been stored in a blast$-$proof storage unit with concrete walls in an area distant from a chemical plant where the chemicals are used. On a hot day, the air temperature has reached $40\backslash$deg C and the wind is blowing such that the heat transfer coefficient on the exterior wall surfaces area is $50$ W$/$m$2-$K$.$The $10$ cm thick walls had been at $25\backslash$deg C$,$ but something has caused the chemicals inside to ignite. Monitoring instruments indicate that the interior room temperature quickly reached and stabilized at $205\backslash$deg C$.$ The walls of the storage unit have a thermal conductivity of $0\mathrm{.}58$ W$/$m$-$K$,$ density $1910$ kg$/$m$3,$ and specific heat capacity of $920$ J$/$kg$-$K$.$Find the temperature profile through a wall, assuming that at time t $=0,$ the temperature of the left face $($interior$)$ is raised to $200$ oC while the right face $($exterior$)$ is exposed to blowing air at $40$ oC$.$Estimate the time required to approach steady state using the explicit method with the following conditions:a$)11$ nodes in this system with a time step of $65$ s$.$b$)21$ nodes in this system with a time step of $21$ s$.$c$)$ How do the answers change with $=21?$ Should a time step even smaller be used to get an accurate answer or was $65$ s adequate? Use excel