*Question T3B03:
What are the two components of a radio wave?*  

*Correct Answer is  C: Electric and magnetic fields*  

### AI Response: (may contain errors)  

The correct answer to the question about the two components of a radio wave is **C: Electric and magnetic fields**. 

### Explanation of the Correct Answer:
- **Electric and Magnetic Fields**: A radio wave is an electromagnetic wave, which means it consists of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation. This is described by Maxwell's equations, which govern the behavior of electric and magnetic fields.

### Why the Other Choices are Incorrect:
- **A: Impedance and reactance**: These terms relate to the properties of circuits and components, not the fundamental components of a radio wave. Impedance is the total opposition to current flow in an AC circuit, while reactance is the opposition due to capacitance or inductance.
  
- **B: Voltage and current**: These are electrical quantities that describe the flow of electricity in a circuit. They do not represent the components of a radio wave itself.
  
- **D: Ionizing and non-ionizing radiation**: This classification refers to the energy of radiation and its ability to ionize atoms. While radio waves are non-ionizing, this choice does not address the specific components of a radio wave.

### Useful Concepts:
- **Electromagnetic Wave Propagation**: Radio waves propagate through space as oscillating electric and magnetic fields. The speed of these waves in a vacuum is given by the equation:
  
  $$c = f \cdot \lambda$$
  
  where:
  - $c$ = speed of light (approximately $3 \times 10^8$ m/s)
  - $f$ = frequency of the wave in hertz (Hz)
  - $\lambda$ = wavelength in meters (m)

Understanding these concepts will help you grasp the nature of radio waves and prepare effectively for the Extra Class exam.