Under the present definition, what is the status of the old metal cylinder, the international prototype of the kilogram?
Its mass is still exactly 1 kg by definition
Its mass now has to be measured by experiment, like that of any other object✓Ճիշտ պատասխան
It was destroyed when the new definition took effect
It now defines the gram instead of the kilogram
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The old definition fixed the prototype at exactly one kilogram and left the Planck constant to be measured. The new definition swaps the two around: the constant is now exact, and the cylinder is simply an object whose mass must be determined.