4.9 The Stefan-Boltzmann law can be employed to estimate the rate of radiation of energy H from a surface, as in H = AeoT where H is in watts, A = the surface area (m³), e = the emissivity that characterizes the emitting properties of the surface (dimension- less), o = a universal constant called the Stefan-Boltzmann con- stant (= 5.67 x 10-8 w m-2 K*), and T = absolute temperature (K). Determine the error of H for a steel plate with A e = 0.90, and T = 650 ± 20. Compare your results with the exact error. Repeat the computation but with T = 650 ± 40. Interpret 0.15 m, %3D your results.

4.9 The Stefan-Boltzmann law can be employed to estimate the rate of radiation of energy H from a surface, as in H = AeoT where H is in watts, A = the surface area (m³), e = the emissivity that characterizes the emitting properties of the surface (dimension- less), o = a universal constant called the Stefan-Boltzmann con- stant (= 5.67 x 10-8 w m-2 K*), and T = absolute temperature (K). Determine the error of H for a steel plate with A e = 0.90, and T = 650 ± 20. Compare your results with the exact error. Repeat the computation but with T = 650 ± 40. Interpret 0.15 m, %3D your results.