Which wavelength is considered non-ionizing in the visible light spectrum?

The correct answer, which represents the wavelength considered non-ionizing in the visible light spectrum, encompasses 400-700 nm. This range corresponds to the wavelengths of light that can be perceived by the human eye, including all the colors visible in a rainbow: violet, blue, green, yellow, orange, and red.

Non-ionizing radiation refers to electromagnetic radiation that does not carry enough energy to ionize atoms or molecules, meaning it cannot remove tightly bound electrons. The visible light spectrum falls within this category of non-ionizing radiation, as the energy levels of the photons within this range are insufficient to cause ionization of biological tissues.

In contrast, wavelengths shorter than 400 nm, such as those in the ultraviolet range, and even shorter wavelengths like X-rays, are capable of causing ionization and can pose health risks, such as skin damage or cellular alteration. Therefore, emphasizing the visible spectrum as non-ionizing supports its safety for various applications, including therapeutic and cosmetic treatments in electrology.