Lyman was able to see emission lines with n_f = 1 in the ultraviolet region. Why are n_f =2 not observed?

• A. Because transitions to n_f = 2 produce emission lines that lie in the visible portion.
• B. Because transitions to n_f = 2 produce invisible emission lines
• C. Because transitions to n_f = 2 produce emission lines that do not exist
• D. Because transitions to n_f = 2 produce emission lines that lie in the infrared region
• E. Because transitions to n_f = 2 do not exist

Answer: (A)