What is measurement?
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The process of measuring unknown quantities with known standards quantities is termed as measurement

Measurement is the process of finding the length, size, or quantity of a substance. ... A physical quantity (like length) has to be measured with respect to some fixed quantity. A fixed quantity with respect to which a physical quantity is measured is called a unit. A unit is used as a standard of measurement.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up