The SI standard of time is based on_____________?

Correct answer: E. none of these

  • A. the daily rotation of the earth
  • B. the frequency of light emitted by Kr86
  • C. the yearly revolution of the earth about the sun
  • D. a precision pendulum clock
  • E. none of these

Explanation

The SI second is defined using the frequency of radiation from the caesium-133 atom, specifically 9,192,631,770 cycles. Since no option mentions caesium-133, none of the listed statements is correct.

Last updated

Related questions