Snell's law gives a linear sin i vs. sin r graph

Steps:

• Snell's law states n_air sin i = n_glass sin r; since n_air ≈ 1, sin i = n sin r where n is constant.
• Plotting sin i (y-axis) against sin r (x-axis) yields sin i proportional to sin r.
• This produces a straight line through the origin with slope n.
• Experimental data should approximate this line, confirming the graph's linearity.

Why A is correct:

• A shows a straight line through the origin, matching sin i = n sin r from Snell's law.

Why the others are wrong:

• B: Curved line violates the constant refractive index in Snell's law.
• C: Line not through origin implies incorrect zero-angle refraction.
• D: Non-linear or scattered points contradict the proportional relationship.

Final answer: A