An electromagnetic wave cannot have a finite frequency and an infinite wavelength. The frequency and wavelength of an electromagnetic wave are inversely proportional to each other and are related by the equation:
c = λν
where: c is the speed of light in a vacuum (approximately 3 x 10^8 meters per second), λ (lambda) is the wavelength of the wave, and ν (nu) is the frequency of the wave.
This equation shows that as the wavelength increases, the frequency decreases, and vice versa. The product of the wavelength and the frequency always equals the speed of light.
If the wavelength were infinite, it would imply that the frequency is zero, which contradicts the nature of electromagnetic waves. Electromagnetic waves consist of oscillating electric and magnetic fields, and these oscillations are characterized by a specific frequency.
It's worth noting that electromagnetic waves span a broad range of frequencies and wavelengths, from extremely low frequencies (such as radio waves with long wavelengths) to extremely high frequencies (such as gamma rays with short wavelengths). However, within the electromagnetic spectrum, both the wavelength and the frequency are always finite and related through the equation mentioned above.