Lines of Balmer series appear in ________ region.

Explanation

To answer the question "Lines of Balmer series appear in ________ region," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Balmer Series**: The Balmer series refers to the set of spectral lines that are emitted when an electron transitions from a higher energy level (n ≥ 3) to the second energy level (n = 2) in a hydrogen atom.

2. **Draw the Energy Level Diagram**:
- The energy levels of the hydrogen atom are represented as n = 1, n = 2, n = 3, n = 4, and so on.
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