The bending of waves as they enter a new medium at an angle is called

• A. Refraction
• B. Reflection
• C. Diffraction
• D. Transmission

Answer: (A)

Refraction is the bending of waves as they pass from one medium into another at an angle. When a wave enters a new material, its speed changes because the new medium has different properties. Because different parts of the wavefront cross the boundary at different speeds, the direction of the wave changes as it moves into the second medium. That’s why a straw looks bent when it’s placed in a glass of water, for example.

Reflection would be bouncing off the boundary, not passing into the new medium. Diffraction involves waves bending around edges or through openings, not the change in direction caused by entering a different material. Transmission is simply the passage of wave energy through a medium, which may or may not involve any change in direction.