Question

The shortest wavelengths emitted in the hydrogen spectrum corresponding to different spectral series are:
(A) Pfund series
(B) Balmer series
(C) Brackett series
(D) Lyman series.
The wavelengths arranged correctly in decreasing order are_______.
Fill in the blank with the correct answer from the options given below.

• A. (A), (B), (C), (D)
• B. (A), (C), (B), (D)
• C. (B), (A), (D), (C)
• D. (A), (C), (D), (B)

Answer 1

The Correct Option is B

The hydrogen spectrum is defined by distinct spectral series, each arising from electron transitions between energy levels. Within each series, the shortest wavelength is observed during a transition from the highest energy levels to the lowest energy level of that specific series. Ordered by increasing shortest wavelength (from smallest to largest), these series are:

1. Lyman series (ultraviolet region): Transitions terminate at n=1. The shortest wavelength results from the transition from n=∞ to n=1.
2. Balmer series (visible region): Transitions terminate at n=2. The shortest wavelength is produced by the transition from n=∞ to n=2.
3. Paschen series (infrared region): Transitions terminate at n=3.
4. Brackett series (infrared region): Transitions terminate at n=4.
5. Pfund series (far infrared region): Transitions terminate at n=5. The shortest wavelength is obtained from the transition from n=∞ to n=5.

Consequently, arranging these series in order of decreasing wavelength (from longest to shortest) yields:
(A) Pfund series
(C) Brackett series
(B) Balmer series
(D) Lyman series
The correct sequence is therefore: (A), (C), (B), (D)