wavelength of one meeter rod ki kya hogi

Hello There!

Your question is a bit confusing but somehow I managed to understand that you are asking about the definition of a metre in terms of wavelength.

You must have known that, the definition of a metre which is the SI of one of the fundamental Physical Quantities, has changed throughout history many times.

In 1960, 11th CGPM agreed on a new definition of a metre where, the s tandard for the metre was redefined to be 1 650 763.73 wavelengths of a particular orange-red light emitted by atoms of krypton-86 ( a particular isotope, or type, of krypton ) in the gas discharge tube.

Hope this resolves your query.