Final answer:
The magnification change from low power (6X) to medium power (20X) is a simple difference of the two, resulting in an increase of 14X. So, answer (c) 14X is correct.
Step-by-step explanation:
To calculate the magnification when the low power is 6X and the medium power is 20X, we need to understand that the total magnification of a microscope is the product of the magnifications of the objective lens and the eyepiece. In this case, however, the student is likely asking about the change from low power to medium power magnification, not the total magnification using an eyepiece. Therefore, the magnification does not increase multiplicatively, but we rather switch from a 6X to a 20X objective lens.
The change in magnification from 6X (low power) to 20X (medium power) is simply the difference between the two magnifications. This is calculated as:
20X (medium power) - 6X (low power) = 14X
So, the answer is (c) 14X, which represents the increase in magnification when switching from the low power objective to the medium power objective on a microscope.