The waves which cannot travel without medium are

Options

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

Answer

To solve the question "The waves which cannot travel without medium are," we will follow these steps:

### Step 1: Understand the Types of Waves
There are two main types of waves: mechanical waves and non-mechanical waves.

### Step 2: Define Mechanical Waves
Mechanical waves are waves that require a medium (solid, liquid, or gas) to travel. Without a medium, these waves cannot propagate.

### Step 3: Provide Examples of Mechanical Waves
An example of a mechanical wave is a sound wave. Sound waves travel through air, water, or solids but cannot travel through a vacuum.

### Step 4: Define Non-Mechanical Waves
Non-mechanical waves do not require a medium to travel. They can propagate through a vacuum.

### Step 5: Provide Examples of Non-Mechanical Waves
Examples of non-mechanical waves include electromagnetic waves such as light waves, radio waves, and X-rays. These waves can travel through the vacuum of space.

### Step 6: Identify the Answer
Since the question asks for waves that cannot travel without a medium, the answer is mechanical waves. Specifically, sound waves are an example of waves that cannot travel without a medium.

### Final Answer
The waves which cannot travel without a medium are mechanical waves, with sound waves being a primary example.

---