Answer: Both A and C.
- A Speed in vacuum / speed in medium
- B Speed in medium / speed in vacuum
- C Wavelength in vacuum / wavelength in medium
- D Both A and C
Correct answer: D. Both A and C
Explanation: n = c/v = lambda_vacuum / lambda_medium. Both are equivalent definitions of refractive index.
Concave mirror ray construction: a ray parallel to the axis reflects through F, and a ray through F reflects parallel, locating the inverted real image. Image: Maxmath12, CC0, via Wikimedia Commons.
Concept context
Reflection, refraction, lenses, mirrors, total internal reflection.