Final answer:
The statement that the working distance using a 4X lens is less than when using a 10X lens is false. As magnification increases, the working distance decreases.
Step-by-step explanation:
When focused on a specimen, the working distance using a 4X lens is greater than when using a 10X lens. This statement is false. The working distance is the distance between the objective lens and the specimen on the slide. As you increase the magnification by switching to a lens with a higher power, such as going from 4X to 10X magnitude, the working distance decreases. This means there is less space available between the lens and the specimen, leading to a much smaller slice of the specimen being in focus.
Microscopes with objective lenses of higher magnifications and numerical apertures (NA) are designed to be closer to the specimen, which reduces the working distance. This is an important consideration as it influences how microscopists handle specimens and adjust the focus of the microscope. Parfocal design ensures that once a specimen is focused with one lens, only minor adjustments are needed when switching to another lens.