When a wave strikes an object and bounces off it, this event is called what?

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

Answer: (B)

Reflection happens when a wave hits a surface and bounces back instead of passing through or being absorbed. The key idea is the wave is redirected back from the surface—for smooth surfaces, the angle at which it arrives (the incidence) roughly equals the angle at which it leaves (the reflection). This is what you see with light in a mirror or with sound producing an echo off a wall.

Absorption would mean the wave’s energy is taken up by the material, possibly warming it. Refraction is the bending of waves as they enter a different medium and change speed. Diffraction is the bending and spreading of waves as they pass around edges or through openings.