The gas used in beacon lamps is 

Options

A. `N e`
B. `He`
C. `Ar`
D. `Kr`

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the gas used in beacon lamps. Beacon lamps are typically used for signaling and visibility purposes.

2. **Identifying the Options**: The options provided are neon, helium, argon, and krypton. We need to determine which of these gases is commonly used in beacon lamps.

3. **Analyzing the Characteristics of the Gases**:
- **Neon**: Known for its bright orange-red glow when electrified. It is commonly used in advertising signs and is visible from long distances.
- **Helium**: While it is used in balloons and some lighting applications, it does not have the same visibility characteristics as neon.
- **Argon**: Often used in light bulbs and some types of lasers, but not specifically known for beacon lamps.
- **Krypton**: Used in some types of high-performance lighting but is not the primary gas for beacon lamps.

4. **Connecting Characteristics to Use**: The gas used in beacon lamps should be visible from a long distance and have good penetrating power through fog or mist. Neon fits this description well.

5. **Conclusion**: Based on the analysis, the gas used in beacon lamps is **neon**.

**Final Answer**: The gas used in beacon lamps is **neon**.

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