Final answer:
Materials typically become warmer when they absorb light. The absorbed light energy raises the temperature of the material as the energy of the light wave is captured by atoms or molecules, which is part of the heat transfer by radiation process.
Step-by-step explanation:
Materials generally become warmer when light is absorbed by them rather than when it is transmitted. When light is absorbed, the energy of the light wave is captured by the material's atoms or molecules, which increases the kinetic energy of the particles and results in a rise of temperature. This concept is a key aspect of the heat transfer by radiation process, where electromagnetic radiation such as microwaves, infrared radiation, or visible light is interacting with matter.
A simple example of this is the warming of the Earth by the Sun, where sunlight is absorbed by the surface, heating it. In contrast, transmission occurs when light passes through a material without raising its temperature significantly—this is why glass, being transparent, allows light to pass through without getting much hotter. It's the absorbed light that contributes to the increase in temperature — demonstrated by the way darker materials, which absorb more light, get warmer than lighter materials with higher albedo.