The standard unit of length, the meter, is now defined with reference to
A) a meridian on the Earth.
B) the French metre.
C) the speed of light.
D) a platinum-iridium bar.
E) a member of the royal family.

Question

Quizplus · Accepted Answer

The meter is currently defined as the length of the path traveled by light in a vacuum during a time interval of 1/299,792,458 of a second. This definition is based on the speed of light in a vacuum, which is a fundamental constant of nature.

The Standard Unit of Length, the Meter, Is Now Defined