$6.$ A rectangular fin is made of aluminum with a thermal conductivity of $237$ W$/$mK$.$ The fin has a thickness of $0\mathrm{.}5$ cm$,$ a length of $20$ cm$,$ and a width of $10$ cm$.$ The temperature at the base of the fin is $100\backslash$deg C$,$ and the ambient temperature is $20\backslash$deg C$.$ The heat transfer coefficient between the fin and the ambient air is $50$ W$/$m$^2$K$.$ Determine the rate of heat transfer from the fin.