Which of the following does not change while light travels from one medium to another?

Which of the following does not change while light travels from one medium to another?

  1. Velocity
  2. Wavelength
  3. frequency
  4. Refractive index
  5. None of the above/More than one of the above.

ANSWER:  Frequency & Refractive index  hence answer is (5)

Details: The value of the Refractive index depends on the material type and frequency does not change while light pass through one medium to another.