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The ionisation energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between

Asked in CBSE AIPMT 2009 · Number of spectral lines

• (1) n=3 to n=2 states
• (2) n=3 to n=1 states
• (3) n=2 to n=1 states
• (4) n=4 to n=3 states

Step-by-step solution

Why the other options are wrong

• (1) n=3→2 would be the longest wavelength only if the atoms had stopped at n=3, which yields 3 lines rather than 6.
• (2) n=3→1 is a wide energy gap and so a short wavelength, and it also assumes excitation only to n=3.
• (3) n=2→1 is the widest gap available here, giving the shortest wavelength rather than the longest.

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