Select wrong statement from the following - Electomagnetic waves

Options

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

Answer

To solve the question of selecting the wrong statement about electromagnetic waves, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: Electromagnetic waves are transverse.
- **Analysis**: This statement is correct. Electromagnetic waves consist of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation. Thus, they are classified as transverse waves.

2. **Statement 2**: Electromagnetic waves travel in free space at the speed of light.
- **Analysis**: This statement is also correct. In a vacuum (free space), electromagnetic waves propagate at the speed of light, which is approximately \(3 \times 10^8\) m/s.

3. **Statement 3**: Electromagnetic waves are produced by accelerating charges.
- **Analysis**: This statement is correct as well. When a charge accelerates, it creates changing electric and magnetic fields, which propagate as electromagnetic waves.

4. **Statement 4**: Electromagnetic waves travel with the same speed in all mediums.
- **Analysis**: This statement is incorrect. The speed of electromagnetic waves varies depending on the medium they are traveling through. The speed can be calculated using the formula:
\[ v = \frac{c}{n} \]
where \(c\) is the speed of light in vacuum and \(n\) is the refractive index of the medium. Different materials have different refractive indices, which means the speed of electromagnetic waves changes in different mediums.

### Conclusion:
The wrong statement among the options provided is **Statement 4**: "Electromagnetic waves travel with the same speed in all mediums."