Question $2$: The components of an electronic system are located in a $1\mathrm{.}5-$m$-$long horizontal duct whose cross section is $\backslash (20\backslash$mathrm$\{$~cm$\}\backslash$times $20\backslash$mathrm$\{$~cm$\}\backslash ).$ The components in the duct are not allowed to come into direct contact with cooling air, and thus are cooled by air at $\backslash (30^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ flowing over the duct with a velocity of $\backslash (200\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$min$\}\backslash ).$ If the surface temperature of the duct is not to exceed $\backslash (65^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ),$ determine the total power rating of the electronic devices that can be mounted into the duct.