Which wavelength type is characterized by the longest wavelength and low frequency?

The correct answer is UVA. This type of ultraviolet (UV) light is characterized by having the longest wavelengths among the UV spectrum, typically ranging from 320 to 400 nanometers. Because of this longer wavelength, UVA light has a lower frequency compared to UVC and UVB rays.

In the context of the electromagnetic spectrum, the wavelength is inversely related to frequency; thus, as the wavelength increases, the frequency decreases. This is why UVA is associated with lower energy and longer wavelengths compared to UVC and UVB, which are shorter in wavelength and higher in frequency.

Visible light, while also important in various contexts, has a different wavelength range that does not extend into the ultraviolet spectrum. Therefore, the characteristics of UVA as having the longest wavelength and low frequency makes it the correct choice in this instance.