Microbiology Lab Midterm Questions and Answers Already Passed

Microbiology Lab Midterm Questions and Answers Already Passed Compound microscope 1. Ocular-eyepiece lens (usually 10x) 2. Objective-nosepiece lenses (commonly 4x, 10x, 45x, and 100x) At what magnification do you use the oil immersion technique? 100x. Total Magnification = Magnification (Objective) x Magnification (Ocular) Important Parts of the Microscope Framework, Stage, and Lens System Framework Arm and base are the structural parts of the microscope which support the basic frame. Stage Holds the slide. The mechanical stage clamps the slide and moves the slide around the stage. Lens System Oculars, Objective, and Condenser Oculars Eyepiece lenses (usually 10x magnification) Objectives Lenses attached to rotatable nosepiece, common magnification of 4x, 10x, 45x and 100x. Parfocalized microscope focusing adjustments are not to be made when... changing the objective lenses. The oil has approximately the same refractive index as glass to prevent... light loss due to diffraction (bending of light rays) which would occur if light traveled from one refractive index to another (eg. glass to air) As magnification of the objective lens increases... the working distance decreases. Working distance distance between the object on slide and the objective lens, when in focus. Condenser directs light towards the objective lens in bright field microscopy. In dark field microscopy, the condenser... directs light at oblique angles away from the objective lens in a manner that allows only objects in the field of view to redirect or scatter light into the objective lens. This causes objects to appear white on a dark field. Iris Diaphragm lever located in the condenser that adjusts the diameter of the cone of light so that it just fills the objective lens. As you close down the Iris Diaphragm... 1. The light intensity decreases 2. Contrast improves 3. Depth of field increases 4. Limit Resolution (with oil immersion lens) Resolution Resolving Power. Expressed as d.