The components of incident radiation, or radiation striking the surface of a body, are what?

• A. Reflected, absorbed and possibly transmitted
• B. Emitted and reflected
• C. Transmitted only
• D. Absorbed only

Answer: (A)

When infrared radiation hits a surface, it doesn’t all do the same thing. The energy can be reflected back, absorbed by the material (often warming it), or transmitted through the material to the other side if the material is transparent for that wavelength. The total incident energy is partitioned among these pathways, and for opaque surfaces transmission is essentially zero, leaving reflection and absorption as the main fates. Emission, on the other hand, is radiation the body itself emits due to its temperature and is not part of the incident radiation. So the components of incident radiation are reflected, absorbed, and possibly transmitted.