The "medium power objective" on a microscope refers to one of the lenses that you can rotate into position to view your specimen. It's typically the middle option in terms of magnification, sitting between the low-power objective (often 4x or 10x) and the high-power objective (usually 40x or 100x).

Here's what you should know about the medium power objective:

* Magnification: It offers a magnification level that's greater than the low-power objective but lower than the high-power objective. Common magnifications for medium power objectives are 10x, 20x, or 40x. This means that the object you're viewing will appear 10, 20, or 40 times larger than its actual size.

* Field of View: It provides a smaller field of view compared to the low-power objective, meaning you can see less of the specimen at once. However, it offers more detail than the low-power objective.

* Working Distance: The working distance, or the space between the objective lens and the specimen, is smaller than with the low-power objective but larger than the high-power objective. This means you need to be more careful not to bump the objective into the slide when using medium power.

* Use: The medium power objective is often used for a good balance between magnification and field of view. It's a good option for observing larger structures within cells, tissues, or small organisms.

In Summary:

The medium power objective provides a good balance between magnification and detail, making it a versatile option for many microscopy applications. It's often the most used objective after the low-power objective.