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:
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)
Assuming the experimental mass of \( {}^{12}_{6}\text{C} \) as 12 u, the mass defect of \( {}^{12}_{6}\text{C} \) atom is____MeV/\( c^2 \).
(Mass of proton = 1.00727 u, mass of neutron = 1.00866 u, 1 u = 931.5 MeV/\( c^2 \))
The binding energy per nucleon of \(^{209} \text{Bi}\) is _______ MeV. \[ \text{Take } m(^{209} \text{Bi}) = 208.98038 \, \text{u}, \, m_p = 1.007825 \, \text{u}, \, m_n = 1.008665 \, \text{u}, \, 1 \, \text{u} = 931 \, \text{MeV}/c^2. \]