An __________ is a sound wave that is reflected back when it strikes a surface.

Options

A. echo
B. oscillation
C. reverberation
D. Both(b) and (c)

Answer

**Step-by-Step Solution:**

1. **Understanding Sound Waves**:
- Sound waves are vibrations that travel through a medium (like air, water, or solids) and can be heard when they reach a listener's ear.

2. **Reflection of Sound Waves**:
- When sound waves encounter a surface (like a wall), they can bounce back. This phenomenon is similar to how light reflects off a mirror.

3. **Identifying the Type of Wave**:
- The sound wave that is produced by a sound source and then strikes a surface is referred to as a "transmitted wave."
- The sound wave that bounces back after hitting the surface is called a "reflected wave."

4. **Defining the Term**:
- The specific term for the sound wave that is reflected back when it strikes a surface is known as an "echo."

5. **Conclusion**:
- Therefore, the complete answer to the question is: "An **echo** is a sound wave that is reflected back when it strikes a surface."

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