In the electromagnetic spectrum, the largest possible wavelength corresponds to the radio waves. Radio waves have the lowest frequency and the longest wavelength in the entire spectrum. They can have wavelengths ranging from meters to kilometers or even longer.
On the other hand, the smallest possible wavelength in the electromagnetic spectrum corresponds to gamma rays. Gamma rays have the highest frequency and the shortest wavelength. They have wavelengths on the order of picometers (10^-12 meters) or even smaller.
To summarize:
- Radio waves have the largest wavelength.
- Gamma rays have the smallest wavelength.