Microscope Lab
If the diameter of your microscope field is 1 mm at low power (10×) and your ocular lens is 10×, then what is the diameter of your field when you switch to the 50× objective lens?
0.2 mm
If a circular object seen in your low-power field (diameter 1 mm) occupies about 1/4 of the diameter of the field, the object's diameter is about ________.
250 μm
If your ocular lens is 10×, and you are using your 45× objective lens to view a slide, the total magnification is ________.
450x
You should always begin observation of specimens with the oil immersion lens.
False
A blood smear is used to diagnose malaria. In patients with malaria, the protozoa can be found near and inside red blood cells. Explain why a microscope capable of high magnification and high resolution would be needed to diagnose malaria.
Structures inside a cell including protozoa are very small and cannot be seen with low magnification.
Histopathology is the use of microscopes to view tissues to diagnose and track the progression of diseases. Why are thin slices of tissue ideal for this procedure?
Thin slices are used so that pathologists can clearly see individual cells for their assessment. Too many layers of cells makes it difficult to focus and hard to see what changes have occurred in the tissues.
The working distance for a 10× objective lens is ________.
a little bit less than the working distance for the 100× objective lens
The microscope field is the ________.
area you see through the lenses of the microscope
You are looking at very lightly stained cells under the microscope, and you want to increase the contrast so that you can see them "better." You ________ the iris diaphragm to ________ the light.
close, dim
The ________ is a substage lens that concentrates light on the specimen.
condenser
As total magnification increases, the depth of field ________.
decreases
As you increase the total magnification of the specimen, the size of the field ________.
decreases
As you increase the total magnification of the specimen, the working distance ________.
decreases
The thickness of the sample that remains in focus at each magnification is called the...
depth of field. Submit
This is the formula for calculating the diameter of an unknown microscope field.
diameter of field A × total magnification of field A = diameter of field B × total magnification of field B
When using the higher power objective lenses, you would use this part of the microscope to focus the specimen.
fine adjustment knob
When observing a slide under a microscope, begin focusing with the ________-power objective lens in place.
lowest Submit
You begin your observations using the ________ lens and the ________ adjustment knob.
lowest-power, coarse
The total magnification of an object can be found by ________.
multiplying the power of the objective lens by the power of the ocular lens
The ________ of the microscope carries three or four objective lenses.
nosepiece
The ability of a microscope to stay in focus when switching between objectives is called...
parfocal
You have learned that the objective lens magnifies the object on the slide, producing the ________ image, and that the ocular lens magnifies that image, forming the ________ image.
real, virtual
The ability to discriminate two close objects as separate is called ________.
resolution
The ability to distinguish between two points as being separate is called...
resolution
Before putting away the microscope in the storage cabinet you must observe all of the following except ________.
rotate the highest power objective lens in position
Microscope specimens have depth, as well as length and width. If you are focused on the middle layer of cells and wish to see the top layer of cells clearly, you should move the ________.
slide further away from the lens
The microscope slide rests on the __________ while being viewed.
stage
When you want to study a slide under the microscope, you place it on the ________.
stage
Your lab microscope is parfocal. This means that __________.
the slide should be almost in focus when changing to higher magnifications
To transport a microscope, hold it ________.
upright, with one hand on its arm and the other hand supporting its base Submit
How do you clean the lenses of your microscope?
with special lens paper and cleaner
The amount of the area of the sample that can be seen in the ocular lens is called the...
working distance.
The distance between the bottom of the objective lens and the sample when the sample is in focus is called the...
working distance.
You are looking at a slide of three crossed threads. Yellow is on the bottom, blue is in the middle, and red is on the top. When you rotate the adjustment knob forward (away from you) on your microscope, the stage rises. You move the adjustment knob to focus on the middle thread. As you rotate the adjustment knob forward, which color thread will come into focus next?
yellow
You are observing the letter "e" under a compound microscope. Which of the following indicates how the image appears as you view it through the ocular lens?
ə
