Concept:Refraction is the bending of light as it passes from one medium into another, which changes its speed.
Reflection is the bouncing back of light from a surface without changing its medium.
Explanation:Statement i is correct because refraction always involves light travelling from one medium into another, so at least two media are required.
Statement ii is not a distinguishing feature because reflection also causes a change in the direction of the ray.
Statement iii is correct because in refraction, light changes speed as it enters a different medium, whereas in reflection its speed remains the same.
Therefore, only statements i and iii are correct.
Answer:D. i and iii only