Which wavelength range is not included in the definition of light as electromagnetic radiation?

The choice of microwaves as the answer highlights a key aspect of the definition of light within the context of electromagnetic radiation. Light is typically defined as the portion of the electromagnetic spectrum that is visible to the human eye, which includes wavelengths ranging from approximately 400 to 700 nanometers. This range encompasses visible light as well as adjacent regions such as ultraviolet (just below visible light) and infrared (just above visible light).

While microwaves are indeed part of the electromagnetic spectrum, they fall outside the visible range, typically ranging from about 1 millimeter to 30 centimeters in wavelength. This places them in a different category entirely, often used for applications such as communication, cooking, and radar, rather than for visual perception.

The other categories listed—visible light, X-rays, and infrared—are all considered types of electromagnetic radiation that impact our understanding of light. X-rays, though not visible to the naked eye, are part of the broader electromagnetic spectrum and play significant roles in medical imaging and other applications. Infrared is also closely associated with heat and is just beyond the visible spectrum, contributing to our understanding of radiation in terms of thermal energy.

Therefore, the reasoning behind why microwaves do not fit into the common definition of light as