Question

How many grams are in 74.0 mg?

Answer 1

Hint: The order of magnitude of mass helps us to compare between different levels of masses. The base unit or the SI unit of mass of a substance is kilograms. Prefixes are used to denote different order of masses.

Complete answer: Milligram is an order of magnitude of mass. It is a submultiple of grams and equivalent to ${{10}^{-3}}$ grams. It is denoted by mg.
\[1mg={{10}^{-3}}g\]
This can be also written as
\[
   1mg=\dfrac{1}{1000}g \\
  or\ 1g=1000mg \\
\]
We can see that 1 gram is 1000 times bigger than a milligram.
Now, we have to convert 74mg to grams. So,
\[
   74mg=74\times {{10}^{-3}}g \\
 74mg=74\times \dfrac{1}{1000}g \\
74mg=0.074g \\
\]
So, 74mg is equivalent to 0.074g.

Additional information:
Unlike quantities like time or length, mass is such a physical quantity that it does not have a predefined maximum or minimum value. It can only have a minimum value that is experimentally derived.
The mass of a proton, which is evidently massless, is said to be the minimum possible value of mass. The mass of a proton is in the range of ${{10}^{-62}}kg$.
Some other historical units of mass outside the order of magnitude are:
- Pound (lb): It is equivalent to 0.453592 kg
- Stone: it is equivalent to 14 lb or 6.35029 kg
- Carat: It is equivalent to 200 mg or 0.0002 kg.

Note: It should be noted that even the SI unit for mass is kilogram, the order of magnitudes are all in terms of grams. So, one must not convert using kilogram as the base.
Kilogram is the only SI unit that has a prefix in its name (kilo-).