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The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is

Asked in NEET 2017 · Spectral series and wavelengths

• (1) 2
• (2) 1
• (3) 4
• (4) 0.5

Step-by-step solution

Why the other options are wrong

• (1) 2 is the ratio of the lower quantum numbers n₁=2 and n₁=1 themselves, rather than of their squares.
• (2) 1 would mean the two series limits fall at the same wavelength; they differ by the factor n₁².
• (4) 0.5 is n₁=1 over n₁=2, the quantum numbers inverted. The answer the other way up would be 0.25, since the limits differ by n₁².

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