Red light differs from blue light as they have:

Red light and blue light are both electromagnetic waves that travel at the same speed $$c$$ in vacuum. However, they are distinguished by their position in the visible spectrum.

Red light has a longer wavelength (approximately 620-750 nm) and correspondingly a lower frequency, while blue light has a shorter wavelength (approximately 450-495 nm) and a higher frequency.

Since the relationship between wavelength and frequency is $$c = \lambda \nu$$, having different wavelengths necessarily means having different frequencies (as $$c$$ is constant).

Therefore, red light differs from blue light as they have different frequencies and different wavelengths.