Final answer:
Minimal light transmission would be observed through a test tube with a high bacterial count due to turbidity. A control tube is used to establish a baseline for zero bacterial growth and accurately measure growth in inoculated tubes.
Step-by-step explanation:
If a researcher found a very high bacterial count in an inoculated test tube, the amount of light that would pass through the test tube would be minimal. This is because a high concentration of bacteria creates turbidity in the culture medium, which scatters and absorbs light, reducing the light transmission. In experiments measuring bacterial growth through turbidity, it is crucial to use a control tube with only broth to establish a baseline for zero bacterial growth. This way, any changes in light transmission in the inoculated tubes can be accurately attributed to bacterial growth. Since bacteria are typically transparent under a brightfield microscope, high bacterial counts can hinder the transmission of light significantly, which can even be observed visually to some extent.
When measuring the bacterial count in a test tube, it is important to measure the transmission of light through a control tube with only broth in it. This is known as a control sample and helps establish a baseline for comparison. By measuring the transmission of light through the control tube, we can determine the amount of light that would have passed through the test tube if there were no bacteria present. This is crucial for accurately assessing the bacterial count and understanding the impact of bacteria on light transmission.