Question

The size of bacteria is $1\mu$ . Find the number of bacteria in $1m$ length.
(A). ${{10}^{3}}$
(B). ${{10}^{6}}$
(C). ${{10}^{4}}$
(D). ${{10}^{5}}$

Answer 1

To calculate the number of bacteria, determine how many parts of micron is equivalent to a meter in the metric system. Since the size of one bacterium is $1\mu$ , by the unitary method, the number of parts of micron in a meter will be equal to the number of bacteria in a meter.

Formula used:
$1\mu ={{10}^{-6}}m$

Complete step by step solution:
One micron ( $1\mu$ ) is one of the measurements of particle size. It is equal to one-millionth part of a metre.
$1\mu ={{10}^{-6}}m$ - (2)
Bacteria are unicellular microorganisms that live in different types of environments. The size of bacteria is given to be 1 micron.
Therefore we can say that there is 1 bacterium in $1\mu m$
From eq (1)

& 1\mu ={{10}^{-6}}m \\\ & \Rightarrow {{10}^{6}}\mu =1m \\\ & \\\ \end{aligned}$$ From the above eq. we can conclude that there are $${{10}^{6}}\mu $$ in $$1m$$ . Since $${{10}^{6}}$$ is the size of 1 bacterium. So there are $${{10}^{6}}$$ bacteria in $$1m$$ . **So, the correct answer is “Option B”.** **Additional Information:** Unitary method is a math technique that is used to find the value for one and use to find required value for a given number or find a number from a given value. For example-Let the price of 1 pen be x, then the price of 10 pens is $$10x$$ . If the price for 5 apples is $$y$$ , the price for one apple is $$\dfrac{y}{5}$$ . **Note:** The sizes of bacteria can range from as small as $$0.3\mu $$ to as large as $$0.7mm$$ . Bacteria are unicellular which means that they are made up of a single cell and a single cell performs all the life functions necessary for existence. In bacteriology, micron is the primary unit of measurement.