Question

$ 1\mu $ is
(A) $ {10^{ - 6}}m $
(B) $ {10^{ - 9}}m $
(C) $ {10^{ - 10}}m $
(D) $ {10^{ - 3}}m $

Answer 1

Hint: To measure the quantities we define a unit for them. Meter is a unit of length. We use scientific notations to write very small or very large numbers. Scientific notation is used when a number between $ 1 $ to $ 10 $ is multiplied by a power of $ 10 $ . Here, we will discuss these scientific notations, particularly, metric prefixes. They make calculations easy and error-free.

Complete answer:
We have a whole table of standard notations shown below in the picture.

A metric prefix is a unit that precedes a basic unit of measurement to indicate a multiple of the unit. All the metric prefixes used are decadic and each prefix has a unique symbol. They are very helpful, to write very large and very small measurements.
From the table, we can see that $ 1\mu $ is a metric prefix $ {10^{ - 6}} $ .
Hence, the correct option is (A) $ {10^{ - 6}}m $ .

Note:
Very common metric prefixes are centi $ \left( c \right) $ , milli $ \left( m \right) $ , micro $ \left( \mu \right) $ , nano $ \left( n \right) $ , pico $ \left( p \right) $ , Giga $ \left( G \right) $ , mega $ \left( M \right) $ , kilo $ \left( k \right) $ , hecto $ \left( h \right) $ .
A metric prefix is always followed by a SI unit.
To write the numbers in scientific notation, there are some rules.
-It is always written in base $ 10 $ and the power of $ 10 $ carries either positive or negative signs.
-The value of the coefficient is (either positive or negative) of $ 10 $ is less than $ 10 $ and equal to or greater than $ 1 $ .
-When we move the decimal to the left the power of $ 10 $ increases. Similarly, when we move the decimal to the right, the power of $ 10 $ decreases.