Question: Differentiate between the resolving power and the magnifying power of a lens. What is meant by the term “parfocal”?

Answer: Resolving Power- the ability to show detail

Magnification- the ability to make objects appear enlarged

Parfocal- different lenses that focus on the same image and can be swtiched without adjusting the microscope

Question: Why is the low-power objective placed in position when the microscope is stored or carried?

Answer: The shortest lens is the least likely to be “smashed” against a slide.

Question: Why is oil necessary when using the 90x to 100x objective?

Answer: Oil has the same optical qualities of glass so it permits continuous stream of light. Oil increases the numerical aperature (aka keeps the light from scattering)

Question: What is the function of the iris diaphragm? The substage condenser?

Answer: The iris diaphragm controls the amount of light passing through the slide or specimen, while the substage condenser focuses a cone of light on the slice or specimen.

Question: What is meant by the limit of resolution?

Answer: Limit of resolution is the shortest distance between 2 parts on a specimen that can be distinguished by the observer,

Question: How can you increase the bulb life of your microscope if the bulb’s voltage is regulated by a rheostat?

Answer: By turning the lamp off and on with the rheostat turned all the way DOWN to the lowest setting it allows for a slow ramping up of the power instead of instantaneously turning on a lamp to the highest and hottest setting.

Question: In general, at what position should you keep your microscope’s substage condenser lens?

Answer: It should be kept half the way between the body and the base.

Question: What are three bacterial shapes you observed?

Answer: The three bacterial shapes are bacillus or rod shaped; coccus or spherical shaped and spirillum or spiral shaped.

Question: How can you increase the resolution on your microscope?

Answer: By using immersion oil

Question: In microbiology, what is the most commonly used objective? Explain your answer.

Answer: 100x, if you got a higher objective you would just have higher magnification but not be able to see detail