5 Consider the metallic surface of Example 12.7. Additional measurements of the spectral, hemispherical emissivity yield a spectral distribution which may be approximated as follows: Determine corresponding values of the

total,hemispherical emissivity e and the total emissive power E at 2000 K. 5) Plot the emissivity as a function of temperature for 500 s TS 3000 K. Explain the variation.