Read the statements below and answer the questions that follow.
(i) Explain why a plane electromagnetic wave described by E(x,t)=E0sin(kx−ωt) must satisfy kω=μ0ε01 in free space.
(ii) Describe qualitatively what happens to the wavelength and frequency if the wave enters a dielectric medium with permittivity ε>ε0 while the source frequency remains unchanged.
(iii) Define amplitude, wavelength, and period for the electric field given above, and explain how each quantity can be identified directly from the mathematical form of the field.