The waves which cannot travel without medium are

Options

A. X-rays
B. Radio waves
C. Light waves
D. Sound waves

Answer

**Step-by-Step Solution:**

1. **Understanding the Types of Waves:**
- Waves can be classified into two main categories: mechanical waves and non-mechanical waves.
- Mechanical waves require a medium (solid, liquid, or gas) to propagate, while non-mechanical waves do not require a medium and can travel through a vacuum.

2. **Identifying Mechanical Waves:**
- Examples of mechanical waves include sound waves, water waves, and seismic waves.
- Sound waves are a prime example of mechanical waves as they need a medium (like air, water, or solids) to travel.

3. **Understanding Non-Mechanical Waves:**
- Non-mechanical waves include electromagnetic waves such as light waves, radio waves, and X-rays.
- These waves can travel through a vacuum, meaning they do not require a medium to propagate.

4. **Analyzing the Question:**
- The question asks for waves that cannot travel without a medium.
- Since mechanical waves require a medium for propagation, we can conclude that sound waves are the answer.

5. **Conclusion:**
- Therefore, the waves which cannot travel without a medium are **sound waves**.

**Final Answer: Sound waves.**

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