Which improvement helps increase accuracy of ray diagrams?

• A. View bases of pins since pins may not be vertical
• B. Keep pins further apart and use more pins
• C. Avoid parallax, explain action and reason
• D. Repeats and average

Answer: (C)

Avoiding parallax errors when drawing ray diagrams is the main idea. Parallax happens when you look from a slight angle, making the diagram lines appear misaligned from the true path of light. If you view the diagram at the correct eye level and position, the rays you draw line up with the actual directions light would take, so the diagram is accurate.

Explaining what the ray is doing and why helps reinforce that accuracy. When you state how a ray behaves at a boundary—why it bends, which angle it makes with the normal, or how it travels in straight lines between interactions—you’re checking that the drawn path matches the physics, not just making lines that look right. This combination of correct viewing position and reasoning about the ray’s behavior ensures the diagram truly represents the light path.

Other options don’t Address the core source of error. Using more pins or spreading pins wider might help with drawing stability in some setups, but it doesn’t fix the fundamental issue of viewing position. Repeating and averaging relates to measurement data, not the accuracy of a static diagram. Viewing the bases of pins to ensure verticality addresses a practical alignment issue, but the most important improvement for accuracy of the diagram is eliminating parallax and articulating the reasoning behind the ray path.