Which of the following statement is incorrect about electromagnetic waves?

Options

A. These are transverse in nature
B. These are produced by accelerating charges
C. They travel with the same speed in all media
D. They travel in free space with the speed of light

Answer

To determine which statement about electromagnetic waves is incorrect, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Option 1: Electromagnetic waves are transverse in nature.**
- Electromagnetic waves consist of oscillating electric (E) and magnetic (B) fields that are perpendicular to each other and to the direction of wave propagation. This characteristic confirms that electromagnetic waves are indeed transverse waves.
- **Conclusion:** This statement is correct.

2. **Option 2: Electromagnetic waves are produced by accelerating charges.**
- It is a well-established fact that electromagnetic waves are generated when electric charges accelerate. This is the fundamental principle behind the generation of electromagnetic radiation.
- **Conclusion:** This statement is also correct.

3. **Option 3: Electromagnetic waves travel with the same speed in all media.**
- The speed of electromagnetic waves in a medium is given by the formula \( v = \frac{1}{\sqrt{\mu \epsilon}} \), where \( \mu \) is the permeability and \( \epsilon \) is the permittivity of the medium. Since these values differ for different media, the speed of electromagnetic waves varies depending on the medium.
- **Conclusion:** This statement is incorrect.

4. **Option 4: Electromagnetic waves travel in free space with the speed of light.**
- In free space (vacuum), the values of permeability (\( \mu_0 \)) and permittivity (\( \epsilon_0 \)) are constants. The speed of electromagnetic waves in free space is given by \( c = \frac{1}{\sqrt{\mu_0 \epsilon_0}} \), which equals the speed of light.
- **Conclusion:** This statement is correct.

### Final Answer:
The incorrect statement about electromagnetic waves is **Option 3**: "They travel with the same speed in all media."

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