Objective lenses come in various magnification powers, with the most common being 4x, 10x, 40x, and 100x, also known as scanning, low power, high power, and (typically) oil immersion objectives, respectively.

The eyepiece, also called the ocular lens, is a low power lens. The objective lenses of compound microscopes are parfocal. You do not need to refocus (except for fine adjustment) when switching to a higher power if the object is in focus on a lower power. The field of view is widest on the lowest power objective.

The 4x objective lens has the lowest power and, therefore the highest field of view. As a result, it is easier to locate the specimen on the slide than if you start with a higher power objective.

Magnification

Low power objectives cover a wide field of view and they are useful for examining large specimens or surveying many smaller specimens. This objective is useful for aligning the microscope. The power for the low objective is 10X. While looking from the side, crank the specimen up as close as it can get to the objective.

When you change from low power to high power on a microscope, the high-power objective lens moves directly over the specimen, and the low-power objective lens rotates away from the specimen. The image should remain in focus if the lenses are of high quality.

When switching to the 100x lens, what should you use? 100x lenses should be used with a few drops of immersion oil to enhance the image.

While many people assume that the bathroom doorknob would be the dirtiest, the NSF found other spots that ranked higher with bacteria, including:

• bathroom light switches.
• refrigerator handles.
• stove knobs.
• microwave handles.

mouth

These Are the Dirtiest Things in Your Home (Which You Should Clean Immediately)

1. Your kitchen sink.
2. The areas surrounding your toilet bowl.
3. Your cleaning sponges and rags.
4. Any kids’ toys lying around.
5. Your cell phone.
6. Your computer’s keyboard.
7. Doorknobs and light switches.

Paper money can carry more germs than a household toilet. They provide hospitable environments for gross microbes. Viruses and bacteria can live on most surfaces for about 48 hours and paper money can transport a flu virus for up to 17 days. After handling money, we recommend washing your hands or using hand sanitizer.

10 of the Dirtiest Things You Touch Every Day

• TOOTHBRUSHES AND TOOTHBRUSH HOLDERS.
• REFRIGERATOR HANDLES.
• CUTTING BOARDS.
• REMOTE CONTROLS.
• PHONES.
• PURSES.
• GROCERY CARTS.
• KEYBOARDS. Staph, Coliform, yeast, and mold are among the tasty treats likely to be hiding in the crannies of your favorite QWERTY keyboard.