It is the ratio of one Joule to one Newton, and when squared, it is the ratio of one Newton to one Pascal.
In 1960, this SI unit was redefined using an orange line in the spectrum of krypton-86. It is the ratio of one Joule to one Newton, and when squared, it is the ratio of one Newton to one Pascal. It was originally defined using a platinum rod, then a platinum-iridium bar in Paris, but its most recent definition is dependent on the speed of light. For 10 points, give this base unit used in measurements of periods, wavelengths, and distances, the SI unit of length.
In 1960, this SI unit was redefined using an orange line in the spectrum of krypton-86.
{meter}