*Question T0C01:
What type of radiation are radio signals?*  

*Correct Answer is  D: Non-ionizing radiation*  

### AI Response: (may contain errors)  

Radio signals are classified as non-ionizing radiation. Here's a breakdown of why this is the correct answer and why the other options are incorrect:

### Correct Answer: Non-ionizing radiation
- **Definition**: Non-ionizing radiation refers to electromagnetic radiation that does not carry enough energy to ionize atoms or molecules. This means it cannot remove tightly bound electrons from their orbits around atoms.
- **Examples**: Radio waves, microwaves, and visible light are all forms of non-ionizing radiation. Radio signals fall into this category, as they operate at frequencies typically below 300 GHz.

### Why the Other Choices are Incorrect:
- **A: Gamma radiation**
  - **Explanation**: Gamma radiation is a form of ionizing radiation that has very high energy and can penetrate most materials. It is produced by radioactive decay and can cause ionization in biological tissues, leading to potential health risks.
  
- **B: Ionizing radiation**
  - **Explanation**: Ionizing radiation includes particles and electromagnetic waves that have enough energy to ionize atoms. This category includes gamma rays, X-rays, and some particles like alpha and beta particles. Radio signals do not have sufficient energy to ionize atoms, so they do not fit this classification.
  
- **C: Alpha radiation**
  - **Explanation**: Alpha radiation consists of helium nuclei emitted from certain radioactive materials. It is a type of ionizing radiation and is not related to radio signals, which are electromagnetic waves.

### Summary
- Radio signals are non-ionizing radiation, meaning they do not have enough energy to ionize atoms.
- Understanding the differences between types of radiation is crucial for safety and regulatory compliance in amateur radio operations. 

This knowledge is essential for the Extra Class exam and helps ensure safe practices in the use of radio frequencies.