There are a number of objections to the metre bar, as the primary standard of length. Some of the objections are as under:
(i) It may be lost or destroyed due to fire or of any such reason.
(ii) It is not easily accessible and reproducible as the unit of a physical quantity should be
(iii) The techniques used for producing the prototype copies of the standard metre, involve the use of microscope and engines.These techniques are not of very high accuracy as required for modern scientific work.
