Question

The spectral series which corresponds to the electronic transition from the levels n₂ = 5, 6,… to the level n₁ = 4 is

• A. Pfund series
• B. Brackett series
• C. Lyman series
• D. Balmer series

Answer 1

The Correct Option is B

The spectral series corresponding to the electronic transition from higher energy levels (\(n_2 = 5, 6, \ldots\)) to a lower energy level (\(n_1 = 4\)) is known as the Brackett series. Let's understand the concept of spectral series and why Brackett series is the correct answer:

The spectral series in the hydrogen atom arise due to electron transitions between different energy levels. These series are named based on the lowest energy level they transition to, and are as follows:

1. Lyman series: Transitions to \(n_1 = 1\) 
2. Balmer series: Transitions to \(n_1 = 2\)
3. Paschen series: Transitions to \(n_1 = 3\)
4. Brackett series: Transitions to \(n_1 = 4\)
5. Pfund series: Transitions to \(n_1 = 5\)

According to the question, the transition is from levels \(n_2 = 5, 6, \ldots\) to \(n_1 = 4\). This directly aligns with the definition of the Brackett series.

Let's rule out other options:

• Lyman Series requires \(n_1 = 1\), which does not match the given \(n_1 = 4\).
• Balmer Series requires \(n_1 = 2\), also not matching \(n_1 = 4\).
• Pfund Series requires \(n_1 = 5\), which again does not align with \(n_1 = 4\).

Therefore, among the given options, the appropriate series for the transition to \(n_1 = 4\) is indeed the Brackett series, making it the correct answer.