Using an appropriate table and simple calculation, identify the shape factors, heat circuit and heat exchange by radiation from floor to other surfaces (side walls and roof) of the furnace shows in Figure 1. 2m 1.5m (A4) 1m (A2) ) (A3) (A1) A1 A2 A3 A4 FLOOR END WALL SIDE WALL ROOF Dimension 2 mx 1.5 m 1 mx 1.5 m 1 mx 2 m 2 mx 1.5 m T 1000K 600K 600K 600K surface emissivity e 0.8 0.5 0.5 0.5 Figure 1 Dimension and characteristic of a thin wall furnace (18 marks)