Why does a convex lens converge parallel rays of sunlight to a single focal point?
Answer and explanation
Correct answer: B. Refraction at the curved lens surfaces bends rays towards the principal optical axis
- Step 1: A convex lens is thicker in the middle. Rays striking the outer curved glass refract at the air-glass and glass-air interfaces. Step 2. Because of lens curvature, rays above the axis bend downward and rays below bend upward, converging at the focal point. Answer: Refraction at the curved lens surfaces bends rays towards the principal optical axis. Why not the others: This convergence is driven by refraction according to Snell's law.
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