Two large plates are maintained at a temperature of 900 K and 500 K respectively. Each plate has an area of 6 m². Compare the net heat exchange between the plates for the following cases. Both plates are black. Plates have an emissivity of 0.5. Given: T1 = 900 K, T2 = 500 K, A = 6 m². To find: (Q12) net Plates have an emissivity of ε = 0.5.