No, an electromagnetic (EM) wave cannot have more than one wavelength. The wavelength of an EM wave is a fundamental property that defines the distance between two consecutive points of the same phase on the wave, such as two successive crests or two successive troughs.
In the context of classical physics and electromagnetic theory, a single EM wave is characterized by a specific wavelength, frequency, and amplitude. These three properties are interrelated through the wave equation:
c = λ * f
where: c is the speed of light in a vacuum (approximately 299,792,458 meters per second), λ (lambda) is the wavelength of the wave, and f is the frequency of the wave.
As you can see from the equation, the speed of light is a constant, and for a given wave, the wavelength and frequency are inversely proportional to each other. If the wavelength changes, the frequency must change accordingly to maintain the speed of light constant.
Therefore, an EM wave cannot simultaneously have multiple distinct wavelengths. Each wave has its unique wavelength, frequency, and corresponding electromagnetic spectrum position, whether it's in the radio, microwave, infrared, visible, ultraviolet, X-ray, or gamma-ray part of the spectrum.