A large collection of hydrogen atoms is initially excited to the seventh Bohr orbit. During complete de-excitation, every possible transition occurs. How many distinct Balmer-series lines can be observed?
Physics · Atomic Structure and X-rays · atomic structure and bohr atomic model
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Question

A large collection of hydrogen atoms is initially excited to the seventh Bohr orbit. During complete de-excitation, every possible transition occurs. How many distinct Balmer-series lines can be observed?

Physics · Atomic Structure and X-rays · atomic structure and bohr atomic model

G1 Physics · Accepted Answer

Balmer-series photons are produced by transitions ending at n = 2. From an initially populated level as high as n = 7, the possible upper levels for Balmer transitions are n = 3, 4, 5, 6 and 7. Therefore the number of distinct Balmer lines is 5. Hence N = 5.