{"id":84736,"date":"2025-06-01T02:47:44","date_gmt":"2025-06-01T02:47:44","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=84736"},"modified":"2025-06-01T02:47:44","modified_gmt":"2025-06-01T02:47:44","slug":"which-one-of-the-following-elements-is-used-as-a-timekeeper-in-atomic","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-elements-is-used-as-a-timekeeper-in-atomic\/","title":{"rendered":"Which one of the following elements is used as a timekeeper in atomic"},"content":{"rendered":"

Which one of the following elements is used as a timekeeper in atomic clocks?<\/p>\n

[amp_mcq option1=”Potassium” option2=”Caesium” option3=”Calcium” option4=”Magnesium” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2018<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nAtomic clocks utilize the precise frequency of electromagnetic radiation absorbed or emitted by atoms during an electron transition between energy levels. Caesium-133 atoms are most commonly used as the primary standard for defining the second in modern atomic clocks. The official SI definition of the second is based on the frequency of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the Caesium-133 atom.
\n<\/section>\n
\nCaesium-133 is the standard element used as a timekeeper in traditional atomic clocks due to the stable and precisely known frequency of its atomic transition.
\n<\/section>\n
\nWhile Caesium clocks are the most widespread standard, other elements like Rubidium are also used, and advanced research is ongoing using elements like Strontium and Ytterbium in optical lattice clocks which offer even higher precision.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following elements is used as a timekeeper in atomic clocks? [amp_mcq option1=”Potassium” option2=”Caesium” option3=”Calcium” option4=”Magnesium” correct=”option2″] This question was previously asked in UPSC CDS-1 – 2018 Download PDFAttempt Online Atomic clocks utilize the precise frequency of electromagnetic radiation absorbed or emitted by atoms during an electron transition between energy levels. Caesium-133 … <\/p>\n

Detailed SolutionWhich one of the following elements is used as a timekeeper in atomic<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1087],"tags":[1114,1236,1128],"class_list":["post-84736","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1114","tag-measuring-instruments-and-scales","tag-physics","no-featured-image-padding"],"yoast_head":"\nWhich one of the following elements is used as a timekeeper in atomic<\/title>\n<meta name=\"description\" content=\"Atomic clocks utilize the precise frequency of electromagnetic radiation absorbed or emitted by atoms during an electron transition between energy levels. Caesium-133 atoms are most commonly used as the primary standard for defining the second in modern atomic clocks. The official SI definition of the second is based on the frequency of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the Caesium-133 atom. Caesium-133 is the standard element used as a timekeeper in traditional atomic clocks due to the stable and precisely known frequency of its atomic transition.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-elements-is-used-as-a-timekeeper-in-atomic\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following elements is used as a timekeeper in atomic\" \/>\n<meta property=\"og:description\" content=\"Atomic clocks utilize the precise frequency of electromagnetic radiation absorbed or emitted by atoms during an electron transition between energy levels. Caesium-133 atoms are most commonly used as the primary standard for defining the second in modern atomic clocks. The official SI definition of the second is based on the frequency of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the Caesium-133 atom. 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