*Question E5C05:
What kind of diagram is used to show the phase relationship between impedances at a given frequency?*  

*Correct Answer is  C: Phasor diagram*  

### AI Response: (may contain errors)  

A phasor diagram is the correct answer for showing the phase relationship between impedances at a given frequency. Here's why:

1. **Why the correct answer is correct:**
   - **Phasor Diagram (C):** A phasor diagram is a graphical representation used in electrical engineering to show the phase relationships between different sinusoidal functions, such as voltages and currents, at a specific frequency. It uses vectors (phasors) to represent the magnitude and phase angle of these quantities, making it easy to visualize how they relate to each other in terms of phase.

2. **Why the other choices are incorrect:**
   - **Venn Diagram (A):** A Venn diagram is used to show logical relationships between different sets, not phase relationships in electrical circuits.
   - **Near Field Diagram (B):** A near field diagram is used to describe the electromagnetic field close to an antenna, not the phase relationship between impedances.
   - **Far Field Diagram (D):** A far field diagram is used to describe the radiation pattern of an antenna at a distance, not the phase relationship between impedances.

3. **Useful Formulas or Rules of Thumb:**
   - In a phasor diagram, the length of a phasor represents the magnitude of the quantity (e.g., voltage or current), and the angle it makes with the horizontal axis represents the phase angle.
   - The phase difference between two phasors can be determined by the angle between them in the diagram.

Phasor diagrams are particularly useful in AC circuit analysis, where understanding the phase relationship between voltages and currents is crucial for solving circuit problems.