Final answer:
30 micrometers This process is crucial in microscopy to accurately determine the size of microscopic entities for various scientific and medical purposes.
Explanation:
The actual size of the cheek cell observed with the 40x objective lens can be calculated using the formula: Actual size = Measured size × Magnification. Given that the measured length is 12 ocular units, and with a 40x objective lens, the magnification is 40. Therefore, the actual size of the cell would be 12 ocular units × 40 (magnification) = 480 units.
However, each ocular unit corresponds to 16 micrometers, so to find the actual size in micrometers, you would multiply 480 units by 16 micrometers per unit, resulting in 7,680 micrometers. To simplify, divide by the total magnification (40x) to get the size at 30 micrometers, which is the final answer.
The formula for calculating the actual size observed through a microscope involves considering both the measured size and the magnification of the objective lens. In this case, the given measurements allowed for a direct conversion from ocular units to micrometers by considering the relationship between the ocular units and the actual size. Therefore, the calculation involved multiplying the measured size by the magnification factor to determine the total units observed.
Subsequently, knowing the relationship between ocular units and micrometers, it was possible to convert the total units observed into micrometers, yielding the final result of 30 micrometers for the actual size of the cheek cell observed under the 40x objective lens. This process is crucial in microscopy to accurately determine the size of microscopic entities for various scientific and medical purposes.