Which term describes how much a ray bends when it travels through its material?

Which term describes how much a ray bends when it travels through its material?

• A. Focal point
• B. Index of refraction
• C. Normal line
• D. Angle of reflection

Answer: (B)

The amount a ray bends when it travels through a material is described by the index of refraction. This property tells you how fast light moves in that material compared with vacuum, and Snell’s law uses the refractive indices on either side of a boundary to determine the new direction. A higher index means light slows more and bends more toward the normal when entering the material from a lower-index medium; conversely, entering from a denser to a rarer medium causes the ray to bend away from the normal. The other terms relate to different ideas: a focal point is where rays converge after passing through lenses, the normal line is simply the line perpendicular to the surface, and the angle of reflection concerns light bouncing off a surface, not how it bends as it travels through a material.

The amount a ray bends when it travels through a material is described by the index of refraction. This property tells you how fast light moves in that material compared with vacuum, and Snell’s law uses the refractive indices on either side of a boundary to determine the new direction. A higher index means light slows more and bends more toward the normal when entering the material from a lower-index medium; conversely, entering from a denser to a rarer medium causes the ray to bend away from the normal. The other terms relate to different ideas: a focal point is where rays converge after passing through lenses, the normal line is simply the line perpendicular to the surface, and the angle of reflection concerns light bouncing off a surface, not how it bends as it travels through a material.