The third in Balmer series corresponds to an electronic transition between which Bohr's orbits in hydrogen

Options

A. `5 rarr 3`
B. `5 rarr 2`
C. `4 rarr 3`
D. `4 rarr 2`

Explanation

To determine which Bohr's orbits correspond to the third line in the Balmer series for hydrogen, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Balmer Series**: The Balmer series describes the spectral lines of hydrogen that result from electronic transitions to the n=2 energy level. The lines in the Balmer series are denoted by the transitions from higher energy levels (n) to n=2.

2. **Identify the Lines in the Balmer Series**: The first few transitions in the Balmer series are:
- **First line**: n=3 to n=2
- **Second line**: n=4 to n=2
- **Third line**: n=5 to n=2

3. **Determine the Third Line**: From the list above, we see that the third line in the Balmer series corresponds to the transition from n=5 to n=2.

4. **Conclusion**: Therefore, the third line in the Balmer series corresponds to the electronic transition between the Bohr orbits n=5 and n=2.

### Final Answer:
The third line in the Balmer series corresponds to the electronic transition between Bohr's orbits n=5 and n=2.

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