The noble gas He was discovered in the chromosphere of sun by________.

Explanation

To answer the question regarding the discovery of the noble gas helium (He) in the chromosphere of the sun, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**: The question asks about the discovery of helium in the chromosphere of the sun. The chromosphere is one of the layers of the sun's atmosphere.

2. **Historical Background**: Helium was first identified in the late 19th century. The discovery was linked to observations made during a solar event.

3. **Observation of Helium**: In 1868, scientists observed a bright yellow line in the spectrum of the sun during a total solar eclipse. This line indicated the presence of a new element.

4. **Identifying the Scientists**: The scientists credited with the discovery of helium in the chromosphere are Pierre Janssen and Norman Lockyer. They were able to identify helium based on the spectral line they observed.

5. **Conclusion**: Therefore, the answer to the question is that the noble gas helium (He) was discovered in the chromosphere of the sun by Pierre Janssen and Norman Lockyer in 1868.

### Final Answer:
The noble gas helium (He) was discovered in the chromosphere of the sun by Pierre Janssen and Norman Lockyer.

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