Which side of the electromagnetic spectrum has higher wavelength?

The correct answer focuses on the nature of the electromagnetic spectrum, which is organized by wavelength. The spectrum ranges from low-energy, long-wavelength radiation to high-energy, short-wavelength radiation.

In this case, radio waves, microwaves, infrared, and red light are all situated at the longer wavelength end of the electromagnetic spectrum. Radio waves have the longest wavelengths, followed by microwaves and infrared radiation, with red light being at the visible spectrum's lower end yet still on the longer wavelength side compared to other visible light colors. This progression from radio waves to red showcases an increase in wavelengths, confirming that these options are all oriented towards the longer end of the spectrum.

In contrast, the other sets of colors listed contain higher-energy, shorter-wavelength forms of electromagnetic radiation. For example, the choices that include violet through gamma rays represent wavelengths that decrease in length and increase in energy, with violet being at the shorter end of the visible light spectrum and gamma rays being among the highest energy and lowest wavelength types of electromagnetic radiation. By understanding the relation between wavelength and the position in the spectrum, it becomes clear why the selection of radio waves, microwaves, infrared, and red light represents the side of the spectrum with the higher wavelengths.