Which one statement below is true? Select one: O a. When an EM wave enters a new medium, its wavelength stays the same and its frequency changes. O b. Light travels more slowly in glass than in air. O c. The electric and magnetic fields oscillate at different frequencies in an EM wave O d. Dispersion only occurs for the visible range of the EM spectrum.
Light travel slower in glass than in air because of glass is denser than air and its refractive index is more than that of air. Therefore, except air, light travels slower in any other medium
Other options are not correct like
When an electromagnetic wave enters a new medium it speed as well as wavelength changes but frequency does not change.
