Since 1967 the standard definition for the second has been based on which of the following?
A)characteristic frequency of the cesium-133 atom
B)average solar day
C)sidereal day
D)Greenwich Civil Time
E)None of the above

Question

Quizplus · Accepted Answer

Since 1967, the standard definition of the second has been based on the characteristic frequency of the radiation emitted by the cesium-133 atom. This is because the atomic clocks based on this principle have been found to be highly accurate and reliable.

Since 1967 the Standard Definition for the Second Has Been