The phenomenon of polarisation of electromagnetic wave proves that the electromagnetic waves are

Options

A. longitudinal
B. transverse
C. neither longitudinal nor transverse
D. both longitudinal and transverse

Answer

To solve the question regarding the polarization of electromagnetic waves and what it proves about their nature, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Polarization**:
- Polarization is a phenomenon that occurs when waves oscillate in a particular direction. For electromagnetic waves, this refers to the orientation of the electric field vector.

**Hint**: Recall that polarization involves the alignment of wave oscillations in a specific direction.

2. **Nature of Electromagnetic Waves**:
- Electromagnetic waves consist of oscillating electric and magnetic fields that are perpendicular to each other and also perpendicular to the direction of wave propagation.

**Hint**: Remember that in electromagnetic waves, the electric field (E) and magnetic field (B) are always perpendicular to each other and to the direction of propagation.

3. **Transverse vs Longitudinal Waves**:
- Longitudinal waves have oscillations in the same direction as the wave travels (like sound waves), while transverse waves have oscillations perpendicular to the direction of travel (like light waves).

**Hint**: Think about how the direction of oscillation relates to the direction of wave travel to distinguish between transverse and longitudinal waves.

4. **Polarization and Wave Type**:
- Only transverse waves can be polarized because their oscillations can be restricted to a particular direction. Longitudinal waves cannot be polarized since their oscillations occur in the same direction as the wave travels.

**Hint**: Consider why only transverse waves can have their oscillations aligned in a specific direction.

5. **Conclusion**:
- Since electromagnetic waves can be polarized, this indicates that they are transverse waves. Therefore, the correct answer to the question is that electromagnetic waves are transverse.

**Hint**: Summarize the key points about polarization and wave types to reinforce your understanding of the relationship between them.

### Final Answer:
The phenomenon of polarization of electromagnetic waves proves that electromagnetic waves are **transverse** waves.