Telescopes operating at this wavelength must be cooled to observe ...

[darbym82]

Telescopes operating at this wavelength must be cooled to observe faint astronomical objects.
 
  A) radio
  B) extreme infrared
  C) visible
  D) X-ray
  E) gamma-ray

Question 2

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.

[adammoses97]

Answer to Question 1

B

Answer to Question 2

B

[darbym82]

TYSM

[elyse44]

Gracias!