*Question T7C08:
Which instrument can be used to determine SWR?*  

*Correct Answer is  D: Directional wattmeter*  

### AI Response: (may contain errors)  

To determine the Standing Wave Ratio (SWR), the correct instrument to use is a directional wattmeter. Here's why:

### Correct Answer: Directional Wattmeter
- A **directional wattmeter** measures the power flowing in a specific direction along a transmission line. 
- It can determine both forward and reflected power, which are essential for calculating SWR using the formula:

$$
SWR = \frac{P_{forward}}{P_{reflected}}
$$

where:
- $P_{forward}$ = power traveling towards the load
- $P_{reflected}$ = power reflected back towards the source

### Why the Other Choices are Incorrect:
- **A: Voltmeter**
  - A voltmeter measures voltage, but it does not provide information about power flow or the direction of that power. Therefore, it cannot be used to calculate SWR.

- **B: Ohmmeter**
  - An ohmmeter measures resistance, not power or voltage. It is used to check the resistance of components, but it cannot determine SWR.

- **C: Iambic pentameter**
  - This is a poetic meter and has no relevance to radio measurements or SWR. It is included as a distractor.

### Summary
- Use a directional wattmeter to measure forward and reflected power for SWR calculations.
- Remember the formula for SWR to help with understanding how to interpret the measurements.