What is used as the standard of time?a.)revolutions of Earth around the Sun, b.)oscillations of a certain type of light emission, c.)rotations of Earth
p.s: I choose C, however, the system stated it is the wrong answer, can someone explain to me why, and what the correct answer is?

Question

What is used as the standard of time?a.)revolutions of Earth around the Sun, b.)oscillations of a certain type of light emission, c.)rotations of Earth
p.s: I choose C, however, the system stated it is the wrong answer, can someone explain to me why, and what the correct answer is?

anonymous · Answer

The most accurate way to calculate time is to hit caesium with  energy and count the pulses.

anonymous · Answer

attachment

anonymous · Answer

i guess the problem itself is not specific enough?