UPSC Prelims Practice Questions — What is ‘One Nation, One Time’?
Q1. Which one of the following is the nodal authority that notified the Legal Metrology (Indian Standard Time) Rules, 2026?
- A. The Department of Legal Affairs under the Ministry of Law and Justice
- B. The Department of Science and Technology under the Ministry of Science and Technology
- C. The Department of Consumer Affairs under the Ministry of Commerce and Industry
- D. The Department of Consumer Affairs under the Ministry of Consumer Affairs, Food and Public Distribution
Q2. Consider the following statements comparing the draft and the final Legal Metrology (Indian Standard Time) Rules:
1. The draft Rules were placed in the public domain in January 2025, whereas the final Rules were notified in August 2026.
2. The final Rules were published in the Official Gazette on the same date on which they were notified.
3. Unlike the draft Rules, the final Rules take effect immediately upon their publication in the Official Gazette.
Which of the statements given above is/are correct?
- The draft Rules were placed in the public domain in January 2025, whereas the final Rules were notified in August 2026.
- The final Rules were published in the Official Gazette on the same date on which they were notified.
- Unlike the draft Rules, the final Rules take effect immediately upon their publication in the Official Gazette.
- A. 1 only
- B. 1 and 2 only
- C. 2 and 3 only
- D. 1, 2 and 3
Q3. The Legal Metrology (Indian Standard Time) Rules, 2026 come into force how many days after their publication in the Official Gazette?
- A. 60 days
- B. 90 days
- C. 180 days
- D. 365 days
Q4. In the context of Indian Standard Time dissemination, 'White Rabbit' refers to which one of the following?
- A. A dedicated set of NavIC satellites that broadcasts coded time signals to authorised ground receivers
- B. The bank of caesium clocks and hydrogen masers that constitutes the National Primary Timescale
- C. A Precision Time Protocol-based optical fibre network for highly accurate clock synchronisation
- D. A shortwave radio time-signal service that transmits IST pips to civilian and maritime users
Q5. Consider the following statements about how Indian Standard Time is realised at the national level and how it reaches users regionally:
1. The five Regional Reference Standard Laboratories under the Time Dissemination Project are located at Ahmedabad, Bengaluru, Bhubaneswar, Faridabad and Hyderabad.
2. IST is realised and maintained at CSIR-NPL through a National Primary Timescale and is kept traceable to Coordinated Universal Time.
3. Dissemination of IST to users is required to be routed exclusively through satellite-based systems, ground network protocols having no role.
Which of the statements given above is/are correct?
- The five Regional Reference Standard Laboratories under the Time Dissemination Project are located at Ahmedabad, Bengaluru, Bhubaneswar, Faridabad and Hyderabad.
- IST is realised and maintained at CSIR-NPL through a National Primary Timescale and is kept traceable to Coordinated Universal Time.
- Dissemination of IST to users is required to be routed exclusively through satellite-based systems, ground network protocols having no role.
- A. 2 only
- B. 1 and 2 only
- C. 2 and 3 only
- D. 1, 2 and 3
Q6. Which one of the following best describes the principal change brought about by the Legal Metrology (Indian Standard Time) Rules, 2026 relative to the position obtaining before them?
- A. IST, hitherto maintained by CSIR-NPL, was transferred to the Bureau of Indian Standards for its realisation and upkeep
- B. IST, hitherto followed as a reference standard, became legally binding as the sole time reference for official and commercial use
- C. IST, hitherto a single national time, was supplemented by a second statutory time zone for the north-eastern States
- D. IST, hitherto derived from foreign satellite sources, was redefined with reference to the 90°E meridian passing through Assam
Q7. The public consultation window provided for the Draft Legal Metrology (Indian Standard Time) Rules, 2025 was of how many days?
- A. 15 days
- B. 21 days
- C. 30 days
- D. 60 days
Q8. India's standard meridian, on which Indian Standard Time is based, lies at how many degrees of longitude east of the Prime Meridian?
- A. 75°00′ E
- B. 82°30′ E
- C. 87°30′ E
- D. 90°00′ E
Q9. Consider the following statements about the Legal Metrology Act, 2009 — the parent framework under which the Indian Standard Time Rules have been made:
1. It replaced the earlier Standards of Weights and Measures legislation of 1976 and its enforcement law of 1985.
2. It received the assent of the President in January 2010 and stands as Act No. 1 of 2010.
3. It is administered at the Union level by the Department of Consumer Affairs.
4. It vests the power to make rules relating to enforcement of weights and measures exclusively in the State Governments.
Which of the above is/are NOT correct?
- It replaced the earlier Standards of Weights and Measures legislation of 1976 and its enforcement law of 1985.
- It received the assent of the President in January 2010 and stands as Act No. 1 of 2010.
- It is administered at the Union level by the Department of Consumer Affairs.
- It vests the power to make rules relating to enforcement of weights and measures exclusively in the State Governments.
- A. 1 and 3
- B. 4 only
- C. 2 and 4
- D. 3 only
Q10. Time-stamping in banking, telecom and power systems demands extreme precision. IST realised at CSIR-NPL is kept traceable to Coordinated Universal Time with an uncertainty of the order of how many nanoseconds?
- A. ±0.29 nanoseconds
- B. ±2.9 nanoseconds
- C. ±29 nanoseconds
- D. ±290 nanoseconds
Q11. India, like China, observes a single time zone across its territory. Russia officially spans how many time zones?