Final answer:
Becky's statement that the cells appear 40 times larger under a 4X objective lens is correct. The total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens, which is typically 10X, leading to a 40X total magnification.
Step-by-step explanation:
Among Erin, Becky, and Stephanie, the correct answer would be with Becky.
When looking through a microscope with a 4X objective lens, the size of the image is not simply 4 times larger.
To determine the total magnification, you have to multiply the magnification power of the objective lens by that of the ocular lens, which is typically 10X.
Therefore, a 4X objective lens multiplied by a 10X ocular lens equals 40X total magnification.
As stated in the light microscopy section, the ocular lens further magnifies the real image by an additional factor of 10, resulting in a magnification that is vastly larger than the object itself.
For example, examining Bacillus cereus cells, which are about 4 µm long, under a microscope using a high power lens would make them appear much larger.
Assuming we use a common 40X high power objective plus the 10X ocular lens, the cells would appear to be 40 * 10 = 400 times larger, which is exactly the light microscope's capacity, as previously indicated.
Therefore, if the students were using the 4X objective lens specifically, the cells would appear to be 4 * 10 = 40 times larger than their actual size.