Question

In defining the standard of length, we are required to specify the temperature at which measurements should be made. Are we justified in calling the length of fundamental quantity, is another physical quantity temperature has to be specified in choosing a standard?

Answer 1

Dear student, The length of an object changes with temperature but the unit for measuring length (f.e., metre) has now been defined in terms of wavelength of light. This is not affected by temperature. Hence, the choice of length as a fundamental units is justified. Regards