Microbiology Post Lab 1

Suppose you forget to add oil immersion when using the oil-immersion objective. Predict what would you likely observe? A.) The image would look sharp because the fine focus adjustment would compensate B.) The image would look dark because the oil adds brightness to the image. C.) The image would look smaller because immersion oil increases magnification. D.) The image would look blurry and would not get into focus when the fine focus known is turned.

D.) The image would look blurry and would not get into focus when the fine focus known is turned.

The resolving power of a microscope is a function of ... A.) the numerical aperture of the lenses B.) the magnifying power of the lenses C.) the wavelength of light D.) both magnifying power and numerical aperture E.) both numerical aperture and wavelength of light

E.) both numerical aperture and wavelength of light

What two adjustments can be made to the condenser? A.) It can be adjusted to modify the brightness of the light from the source B.) Its diaphragm can be opened/closed to regulate amount of light hitting the slide. C.) It can be moved up and down under the stage. D.) It can be moved left/right to position the specimen. E.) It can be adjusted to ensure focused, sharp images to both eyes

B and C are all correct

Starting with the low-power lens when viewing a slide offers what advantage? A.) The larger field of view enables you to easily locate the specimen. B.) The working distance is the smallest with this lens. C.) The specimen is viewed with the greatest magnification. D.) The smaller field of view enables you to easily locate the specimen.

A.) The larger field of view enables you to easily locate the specimen.

Once focus is achieved at one magnification, a higher-power objective lens can be rotated into position without fear of striking the slide. A.) True B.) False

A.) True

Only lint-free, optically safe tissue should be used to wipe off microscope lenses. A.) True B.) False

A.) True

Before the oil immersion lens is rotated into place, you should: A.) center the object of interest and add a drop of oil to slide B.) place a drop of oil on the slide C.) all of the above D.) center the object of interest E.) lower the stage with use of the coarse focus adjustment knob

A.) center the object of interest and add a drop of oil to slide

What should be done before returning a microscope to its storage location? ( check all that apply) A.) Remove the ocular lenses and place on the stage. B.) Adjust the mechanical stage to a low and centered position C.) Remove oil from all lenses and the stage. D.) Wipe the oil immersion lens with fresh oil and a lens wipe to keep lubricated. E.) Rotate the nosepiece to put the low-power lens into position F.) Wrap the cord so it does not hang freely.

B, C, E, and F are all correct

Maximum resolution can be achieved when using the oil immersion lens by implementing what procedures? ( more than one answer) A.) Increase the working distance between lens and slide. B.) Move condenser to highest position. C.) Lower the condenser to the lowest position. D.) Open the diaphragm fully. E.) Increase the light intensity from the source.

B, D, E are all correct

If you are using the 40x objective to observe your specimen and the ocular of your microscope is labeled "10x", what is the total magnification of your specimen? A.) 100X B.) 400X C.) 1000X

B.) 400X

The coarse focus knob can be used to adjust the focus when using any of the objective lenses. A.) True B.) False

B.) False

The total magnification capability of a light microscope is only limited by the magnifying power of the lens system. A.) True B.) False

B.) False

True or False: A light microscope can be used to observe viruses. A.) True B.) False

B.) False

The coarse and fine focus knobs adjust the distance between: A.) the stage and the condenser lens B.) the stage and the objective lens C.) the ocular lenses and your eyes D.) the ocular lenses E.) the objective and ocular lenses

B.) the stage and the objective lens

Identify the reason why the focal distance is important when the oil-immersion objective is used to observe a specimen. A.) Because the focal distance ensures that the maximum amount of light will enter the specimen B.) Because if the focal distance changes the microscope loses its parfocality. C.) Because if the focal distance is changed while using the oil- immersion objective, the objective may touch and scratch/break the glass slide

C.) Because if the focal distance is changed while using the oil-immersion objective, the objective may touch and scratch/break the glass slide

How do you position your hands when carrying the microscope to and from the laboratory bench? A.) Both hands holding the arm. B.) Both hands holding the head of the microscope. C.) One hand holding the arm, the other underneath, holding the base

C.) One hand holding the arm, the other underneath, holding the base

A microscope that maintains the focus of a specimen even when the objective magnification is increased is called _______. A.) diopter B.) phase-contrast C.) Parfocal D.) Parcentral

C.) Parfocal

A microscope's resolving power can be defined in simple terms as A.) The color of the images it produces B.) The size of the images it produces. C.) The clarity of the images it produces.

C.) The clarity of the images it produces.

The ______ the working distance of an objective lens, the ______ the magnification. A.) smaller; lower B.) greater; higher C.) greater; lower

C.) greater; lower