Consider two surfaces, where surface 1 emits radiation to surface 2. How does the intensity compare between Case 1 and Case 2?

• I₁ = I₂

• I₁ > I₂

• I₁ < I₂

Consider an opaque surface with the spectral hemispherical absorptivity shown. What is the hemispherical reflectivity at 2 µm?

• 0.2

• 0.8

• 1

• 0

Consider the spectral hemispherical absorptivity for the four surfaces shown. If the surface is at a temperature of 300 K, which surface may be approximated as gray?

• Surface A

• Surface B

• Surface C

• Surface D

Using Table 12.2, what is the emissive power of a blackbody with a temperature of 400 K from 30 to 50 µm?

• 58.8 W

• 0.0405 W

• 1450 W

• 1400 W

Given the plots shown, what is the spectral hemispherical absorptivity of a 300K surface at a 1.5 µm wavelength?

• 0.05

• 0.9

• 22.9 W

• 0.15