Question

Give reason

metre scale of platinum and iridium scale is preserved at 0c

Answer 1

Answer:

From 1927 to 1960 it was defined as the distance, at 0° Celsius, between the axes of two central lines marked on a reference bar of platinum-iridium held in controlled conditions by the BIPM (the international body governing weights and measures).

Answer 2

$\implies$The formal definition of the meter has gone through several changes. From 1927 to 1960 it was defined as the distance, at 0° Celsius, between the axes of two central lines marked on a reference bar of platinum-iridium held in controlled conditions by the BIPM (the international body governing weights and measures).

cheers !! :)