What Atomic Transition Occurs in Atoms of Hydrogen Gas in the Galactic

question 4

Multiple Choice

What atomic transition occurs in atoms of hydrogen gas in the galactic spiral arms to produce 21-cm radio emission?

• A) The change in the vibrational state of the H atoms in the H₂ molecule
• B) The transition from the n = 2 to n = 1 level in atomic hydrogen
• C) The inversion of the electron spin relative to the proton spin,from parallel to anti-parallel
• D) The change in rotation about an axis perpendicular to the molecular axis in the molecule H₂

---

Definitions:

Total-Product Schedule

A table showing the output or total product resulting from various quantities of inputs or resources, used in production theory.

Marginal Revenue Product

The increase in revenue resulting from the utilization of one extra unit of a factor of production.

Resource

An economic or productive factor required to accomplish an activity or as means to undertake an enterprise and achieve desired outcome.

Marginal Revenue Product

The extra income produced by using an additional unit of a production input, like labor or capital.