Which infrared category requires a source of higher energy input?

• A. Nonluminous infrared radiation
• B. Both
• C. Luminous infrared radiation
• D. Neither

Answer: (C)

Infrared energy comes from two mechanisms: heat-driven emission and luminescent emission. Nonluminous infrared radiation is simply thermal radiation emitted by an object because of its temperature—there’s no extra energy source needed to produce that emission beyond heating the object itself. Luminous infrared radiation, on the other hand, comes from luminescent materials that emit infrared when they’re excited by an external energy source. Because you must supply energy to drive the luminescence, this category requires a higher input of energy to generate the IR emission. Therefore, the source that relies on luminescence needs more energy input, making it the best choice.