The second is defined as the duration of periods of radiation corresponding to the…
PHYSICS · Single correct · A Level · Physics · Measurements and their errors · Measurements and their errors
Problem
The second is defined as the duration of 9192631770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of caesium-133. The principal reason for adopting this atomic standard rather than a fraction of the Earth’s rotation is that it
(a) Eliminates the need for complex laboratory equipment.
(b) Makes it easier to subdivide the second into smaller units such as milliseconds.
(c) Provides a definition independent of variations in Earth’s rotational speed.
(d) Provides greater precision simply because its very high frequency is easier to measure.