Dull surfaces and radiation properties

Steps:

• Dull surfaces scatter incident radiation, leading to low reflection.
• Low reflection implies high absorption of radiation.
• Kirchhoff's law states that absorptivity equals emissivity for a surface in thermal equilibrium.
• Thus, high absorption means high emission, confirming good emitter, good absorber, poor reflector.

Why C is correct:

• C aligns with Kirchhoff's law, where dull surfaces have high emissivity and absorptivity due to low reflectivity.

Why the others are wrong:

• A: Claims good reflector, but dull surfaces reflect poorly.
• B: Claims poor absorber, but dull surfaces absorb well.
• D: Claims poor emitter, but dull surfaces emit radiation efficiently.

Final answer: C