What is the total magnification of the specimen if you are using the 40x objective lens?

Magnification:

• Magnifying/Focusing

• Figuring Total Magnification

1. When viewing a slide through the microscope make sure that the stage is all the way down and the 4X scanning objective is locked into place.
2. Place the slide that you want to view over the aperture and gently move the stage clips over top of the slide to hold it into place.
3. Beginning with the 4X objective, looking through the eyepiece making sure to keep both eyes open (if you have trouble cover one eye with your hand) slowly move the stage upward using the coarse adjustment knobuntil the image becomes clear. This is the only time in the process that you will need to use the coarse adjustment knob. The microscopes that you will be using are parfocal, meaning that the image does not need to be radically focused when changing the magnification.
4. To magnify the image to the next level rotate the nosepiece to the 10X objective. While looking through the eyepiece focus the image into view using only the fine adjustment knob, this should only take a slight turn of the fine adjustment knob to complete this task.
5. To magnify the image to the next level rotate the nosepiece to the 40X objective. While looking through the eyepiece focus the image into view using only the fine adjustment knob, this should only take a slight turn of the fine adjustment knob to complete this task.

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Microscope Magnification

A microscope's total magnification is a combination of the eyepieces and the objective lens. For example, a biological microscope with 10x eyepieces and a 40x objective has 400x magnification. There are however, a few limits to the amount of total magnification that can be reached before empty magnification comes into play. Empty magnification occurs when the image continues to be enlarged, but no additional detail is resolved. This is often the case when higher magnification eyepieces are used. In order to avoid empty magnification, there are a few simple steps that are helpful to follow.

Eyepiece and Objective Combinations for Optimal Magnification

When selecting a combination of eyepieces and objective lenses for the optimal magnification, without ending up with "empty magnification" it is important to consider the numerical aperature (NA) of the objective. The numerical aperture of a microscope objective defines the objective's resolution. Each microscope objective has a minimum and maximum magnification necessary for the details in an image to be resolved. A simple formula for the minimum value is (500 x NA). And for the maximum magnification (1000 x NA). Magnifications higher than this value will result in empty magnification, or an image that has a poor resolution. The table below shows some typical NA values with their corresponding objective and provides a range of useful magnification combinations. The blank boxes in the table would provide empty magnification and should be avoided. For example, pairing 20x eyepieces with a 100x objective would not provide good resolution and would result in empty magnification. To determine this, we took 1.25NA x 1000 = 1250 magnification maximum. However, the combination of the 100x objective x 20x eyepieces = 2000, which is above the maximum magnification.

Range of Useful Magnification based on NA of Objectives

If you have any questions about your microscope's magnification, contact Microscope World.

What is the total magnification of a specimen when you use the 40x objective?

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What is the total magnification of a specimen using the 40x objective quizlet?