Refraction of lights differs from reflection in that, in refraction i. at least two media are involved ii…

Analyze the question: We need to find which statements describe how refraction differs from reflection.

Concept:

• Reflection: light bounces back from a surface and stays in the same medium. Its speed does not change, but its direction changes.
• Refraction: light passes from one medium into another. Its speed changes, and its direction usually changes too (unless it enters along the normal).

Check each statement:

i. At least two media are involved. This is true for refraction, because light must cross a boundary into a second medium. Reflection happens within one medium. So this is a difference. ✔

ii. There is a change in the direction of the ray. This happens in both reflection and refraction. Since it is common to both, it does not distinguish refraction from reflection. ✘ (Also, in refraction along the normal there is no change in direction.)

iii. The speed of the ray changes. This is true for refraction, because the light enters a medium with a different optical density. In reflection the speed stays the same. So this is a difference. ✔

Conclusion: Only statements i and iii are correct.

Answer: D (i and iii only)

Tip: When a question asks how two things differ, cross out any property they share. Both reflection and refraction can change a ray's direction, so that cannot be the difference. Remember: refraction = new medium + new speed.