Difficulty: Easy
Correct Answer: atomic clocks
Explanation:
Introduction / Context:
Modern science and technology depend on ultra-precise timekeeping: GPS, telecommunications, and fundamental physics experiments all require nanosecond-level accuracy. This question targets your knowledge of which devices provide the highest precision for very small intervals.
Given Data / Assumptions:
Concept / Approach:
Atomic clocks use the quantized transition frequencies of atoms (commonly cesium or rubidium) as their fundamental standard. Because these frequencies are extremely stable, such clocks achieve extraordinary precision and are the official basis of the SI second. Quartz clocks are good for everyday use but drift more. Pulsars can be stable rotators, yet astronomical observations limit practicality and resolution in daily metrology.
Step-by-Step Solution:
Identify the target: maximum accuracy in short intervals.Note performance hierarchy: atomic > quartz > mechanical.Exclude astronomical sources (pulsars, white dwarfs) for precise lab-scale timing.Select: atomic clocks.
Verification / Alternative check:
The SI second is defined via the cesium-133 hyperfine transition frequency: time standards use this constant to realize extremely accurate intervals, validating atomic clocks as the gold standard.
Why Other Options Are Wrong:
A) White dwarfs are stars; not timing devices.B) Quartz clocks are less stable than atomic standards.D) Pulsars are precise but impractical for fine interval measurement in labs.E) Pendulum clocks are much less precise.
Common Pitfalls:
Equating regular astronomical phenomena with practical precision. Lab-grade timing requires controllable, accessible standards—hence atomic clocks.
Final Answer:
atomic clocks
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