Final answer:
A thin beam of light is a narrow stream of photons, which could be part of the visible or invisible spectrum like infrared rays. Infrared rays are electromagnetic radiation with longer wavelengths than visible light and are associated with heat.
Step-by-step explanation:
A thin beam of light referred to in the context of the question is likely meant to describe a narrow stream of light particles, known as photons. However, the given term Infrared ray is a specific type of electromagnetic radiation that is invisible to the human eye due to its longer wavelengths than those of visible spectrum. Infrared radiation, which means "below red", is a manifestation of thermal energy from objects and can be detected with various instruments and used in applications such as remote controls, heat lamps, and thermal imaging.
Infrared rays have lower frequencies and longer wavelengths compared to visible light waves. As objects increase in temperature, the intensity of the emitted infrared radiation also increases, which follows the Stefan-Boltzmann law. This property is utilized in thermal detection by satellites and in heating appliances. The range of infrared frequencies extends up to the lower edge of visible light, just below the red part of the spectrum.