hydrogen - 2024 ACF Fall at Cornell

Question

This element is consumed in the CNO cycle and proton-proton chain. For 10 points each:

[10e] Name this most abundant element in the universe. A heavier isotope of this element is deuterium.

ANSWER: hydrogen [or H]

[10h] Transitions in the hyperfine structure of hydrogen create this spectral line, named for its wavelength. Radio waves in this feature are used to observe properties of galaxies.

ANSWER: 21 centimeter line [or 21 cm; reject equivalents of “21 centimeters”, such as “0.21 meters”]

[10m] Radio waves in the 21 centimeter line, unlike visible light, can also pass through this substance undeterred. The interstellar medium consists of gas, cosmic rays, and this substance.

ANSWER: cosmic dust [or extraterrestrial dust or interstellar dust or space dust or star dust]

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Summary


2024 ACF Fall at Claremont Colleges	fall	Y	5	12.00	100%	20%	0%
2024 ACF Fall at Cornell	fall	Y	6	15.00	100%	50%	0%
2024 ACF Fall at Illinois	fall	Y	9	12.22	89%	33%	0%
2024 ACF Fall at Rutgers	fall	Y	7	18.57	100%	71%	14%
2024 ACF Fall at Ohio State	fall	Y	7	17.14	100%	71%	0%
2024 ACF Fall at Washington	fall	Y	1	20.00	100%	100%	0%
2024 ACF Fall at Georgia	fall	Y	9	16.67	100%	56%	11%
2024 ACF Fall at North Carolina	fall	Y	7	14.29	100%	43%	0%

Data


Cornell B	Binghamton B	10	10	20
Cornell C	RIT B	10	10	20
Cornell E	U of Rochester A	10	0	10
RIT A	Syracuse	10	10	20
Penn State	U of Rochester B	10	0	10
Cornell D	Binghamton A	10	0	10