In any one material, all electromagnetic waves have the same

a. wavelength.

b. velocity.

c. frequency.

d. amplitude.

C. frequency. The wavelength of the electromagnetic wave depends on the refractive index of the material the electromagnetic wave is present in, hence the wavelength can change depending on what material the wave is travelling in. The frequency remains the same. The amplitude can change as well depending on the material, e. g in lossy materials the amplitude decreases.