The fountain type of these devices are more accurate due to longer observation times. For 10 points each:
[10m] Name these devices, examples of which include the new NIST-F4. These precision devices rely on electronic transitions in laser-cooled atoms, usually cesium.
ANSWER: atomic clocks [accept cesium atomic fountain clocks; prompt on clocks]
[10h] The resonant frequency of cesium-133 used in atomic clocks comes from this type of transition. The interaction between electron angular momentum and nuclear angular momentum breaks energy level degeneracy and creates this transition type.
ANSWER: hyperfine transition [accept hyperfine structure; reject “fine structure”]
[10e] A new generation of more accurate atomic clocks are named for using frequencies in this range, compared to the microwave transitions of cesium. This region of the electromagnetic spectrum has wavelengths slightly longer than ultraviolet.
ANSWER: visible spectrum [or visible light; or optical spectrum; or optical light; accept optical clocks; accept optical atomic clocks]
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