How do you calculate the width of Bacterium B, which is 3 ocular units wide?

The width of a bacterium observed under a microscope can be calculated by determining how many ocular units correspond to a specific real-world measurement in micrometers (µm). In this case, if Bacterium B is measured to be 3 ocular units wide and the correct conversion factor is 6µm per ocular unit, the calculation is straightforward.

By multiplying the number of ocular units by the conversion factor gives the actual width of the bacterium in micrometers:

3 ocular units × 6µm/ocular unit = 18µm.

This method is crucial for accurately quantifying the size of microorganisms, allowing researchers to count and analyze their dimensions effectively. The choice of 6µm indicates that, in this particular microscope setup, each ocular unit represents 6 micrometers, and thus it’s the correct factor to use for such calculations. The other choices present different values for conversion which would not yield the correct width for Bacterium B based on the value given for ocular units.