Ionization of Hydrogen in H II Regions Is Most Visible

question 50

Multiple Choice

Ionization of hydrogen in H II regions is most visible at

• A)12,367 nm, the Paschen alpha line.
• B)656.3 nm, Balmer alpha line for 3-2 electron transition.
• C)21 cm in the radio region for the spin-flip of its electron.
• D)121.3 nm, the Lyman alpha ultraviolet line for 2-1 electron transition.
• E)473.2 nm, the blue-green emission line for 4-2 electron transition.

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