Question

Why can't we use an angul (finger) or mutthi (fist) as a standard unit of measurement of length?

Answer 1

Hint :The modern version of the metric system is the International System of Units (SI). It is the only method of measurement recognised by virtually every nation on the planet. It is made up of seven base units: the second (the unit of time with the symbol s), metre (length, m), kilogramme (mass, kg), ampere (electric current, A), kelvin (thermodynamic temperature, K), mole (amount of matter, mol), and candela (luminous intensity, cd). The structure allows for an infinite number of additional units, known as derived units, which are often defined as products of the base units' powers.

Complete Step By Step Answer:
The modern version of the metric system is the International System of Units (SI). It is the only method of measurement recognised by virtually every nation on the planet. It is made up of seven base units: the second (the unit of time with the symbol s), metre (length, m), kilogramme (mass, kg), ampere (electric current, A), kelvin (thermodynamic temperature, K), mole (amount of matter, mol), and candela(luminous intensity, cd). The structure allows for an infinite number of additional units, known as derived units, which are often defined as products of the base units' powers.
When expressed in the unit ms⁻¹, the metre (m) is defined as 299,792,458 when expressed in the unit ms⁻¹, where the second is defined in terms of ∆vCs.
A physical artefact - two marks inscribed on a platinum-iridium bar - once identified the metre. The evolution of the concept of the metre is explained in The Length - Evolution from Measurement Standard to a Fundamental Constant. The NIST Length Timeline allows you to monitor these changes over time.
Since different people's body parts are different sizes, we can't use an angul (finger) or mutthi (fist) as a common unit of length measurement. As a result, it can cause uncertainty.

Note :
A physical artefact - two marks inscribed on a platinum-iridium bar - once identified the metre. The evolution of the concept of the metre is explained in The Length - Evolution from Measurement Standard to a Fundamental Constant. The NIST Length Timeline allows you to monitor these changes over time.