We will have the following:
First, we remember that thermal conductivity is given by:
[tex]Q(t)=|\frac{k\cdot A\cdot(T_h-T_c)}{d}|[/tex]So, we replace the values and solve, that is:
[tex]Q(t)=|\frac{(0.80J/s\cdot m\cdot C)(0.8m\cdot0.6m)(20C-2C)}{0.005m}|\Rightarrow Q(t)=|\frac{6.912J\cdot m/s}{0.005m}|[/tex][tex]\Rightarrow Q(t)=|1382.4J/s|[/tex]So, the rate is 1382.4 Joules per second.