Which type of electromagnetic wave is characterized by low frequency and large wavelength?

The choice of radio wave as the correct answer is based on the fundamental properties of electromagnetic waves. Radio waves are characterized by their low frequency and large wavelength compared to other types of electromagnetic radiation. The frequency of radio waves typically ranges from about 3 Hz to 300 GHz, while their wavelengths can span from several millimeters to thousands of meters.

This contrasts with infrared waves, which have higher frequencies and shorter wavelengths, typically ranging from about 300 GHz to 430 THz and having wavelengths from about 700 nm to 1 mm. Similarly, X-rays have significantly higher frequencies and much shorter wavelengths, generally from about 30 petahertz to 30 exahertz, with wavelengths under 10 nm. Microwaves, while having longer wavelengths than infrared and X-rays, still fall into a higher frequency range than radio waves, usually between 300 MHz and 300 GHz with wavelengths from 1 mm to 30 cm.

Thus, the distinct characteristics of radio waves make them the type of electromagnetic wave that is low in frequency and large in wavelength.