Which of the following noble gases is used in miner's cap lamp ?

Options

A. Helium
B. Neon
C. Argon
D. Krypton

Explanation

To solve the question "Which of the following noble gases is used in miner's cap lamp?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Noble Gases**:
- The noble gases include Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).

2. **Research the Uses of Each Noble Gas**:
- **Helium (He)**: Commonly used in balloons due to its lighter-than-air properties.
- **Neon (Ne)**: Used in neon signs and fluorescent lamps.
- **Argon (Ar)**: Often used to provide an inert atmosphere in welding and other metallurgical processes.
- **Krypton (Kr)**: Known for its use in high-efficiency miner's cap lamps.
- **Xenon (Xe)**: Used in high-intensity lamps and flash lamps.
- **Radon (Rn)**: A radioactive gas, not commonly used in practical applications.

3. **Determine the Correct Noble Gas for Miner's Cap Lamp**:
- Among the noble gases listed, Krypton is specifically mentioned as being used in high-efficiency miner's cap lamps.

4. **Conclude the Answer**:
- Therefore, the noble gas used in miner's cap lamps is **Krypton (Kr)**.

### Final Answer:
Krypton (Kr) is the noble gas used in miner's cap lamps.

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