Microscope Principles and Light Structure

Multiply the magnifying power of the objective by that of the eyepiece and by one-tenth of the distance from the eyepiece to the ground glass measured in inches.

The magnification will be twice as great compared to when it is placed 10 inches away.

The amount of detail is limited by the structure of light.

<p>The wave theory of light explains the transmission by undulating or vibrational movement of the ether.</p> Signup and view all the answers

<p>Light travels at a speed of about 186,300 miles per second.</p> Signup and view all the answers

<p>Red light has the longest wavelength, while violet light has the shortest wavelength.</p> Signup and view all the answers

<p>The angstrom unit (Å) is used for measuring light wavelengths.</p> Signup and view all the answers

<p>The angular aperture is defined as the angle between the optical axis and the most divergent rays entering the objective.</p> Signup and view all the answers

<p>Escherichia coli.</p> Signup and view all the answers

<p><em>E. coli</em> will be gradually reduced and replaced by <em>Lactobacillus acidophilus</em>.</p> Signup and view all the answers

<p>Bacteria are necessary for nutrient recycling and the disposal of organic matter.</p> Signup and view all the answers

<p>They convert nitrogen from the air into compounds that plants can utilize.</p> Signup and view all the answers

<p>They convert insoluble proteins, fats, and carbohydrates into soluble compounds.</p> Signup and view all the answers

<p>The souring of milk leads to the preparation of butter and cheese.</p> Signup and view all the answers

<p>Fertile soils contain greater numbers of viable organisms.</p> Signup and view all the answers

<p>They are converted into soluble, diffusible compounds usable by plants.</p> Signup and view all the answers

<p>Changes in dietary habits.</p> Signup and view all the answers

<p>Bacteria convert insoluble proteins, fats, and carbohydrates into soluble, odorless compounds for safe disposal.</p> Signup and view all the answers

<p>Without bacteria, there would be no nitrogen in the soil.</p> Signup and view all the answers

<p>Bacteria cause the souring of milk, which is the initial step in the production of butter and cheeses.</p> Signup and view all the answers

<p>Bacteria and molds are responsible for the ripening of cheese, imparting distinct odors and flavors.</p> Signup and view all the answers

<p>Bacteria play vital roles in various biological processes, aiding in waste decomposition and food production.</p> Signup and view all the answers

<p>Butter, various types of cheeses, and other fermented foods result from bacterial action.</p> Signup and view all the answers

<p>A compound microscope is an optical instrument that uses a combination of lenses to magnify images of small objects.</p> Signup and view all the answers

<p>Bacteria are too small to be seen without significant magnification.</p> Signup and view all the answers

<p>A simple microscope has one lens, while a compound microscope has two sets of lenses (objective and eyepiece).</p> Signup and view all the answers

<p>A fine adjustment screw is used for accurate focusing.</p> Signup and view all the answers

<p>Light forms a real, inverted image after passing through the condenser and objective lens.</p> Signup and view all the answers

<p>A real image is formed by the actual intersection of light rays.</p> Signup and view all the answers

<p>The two types of images are real images and virtual images.</p> Signup and view all the answers

<p>Microscopes enable bacteriologists and biologists to observe and study tiny organisms such as bacteria.</p> Signup and view all the answers

<p>To increase resolution and reduce light loss by capturing aberrant rays.</p> Signup and view all the answers

<p>Other materials may scratch the lens due to their abrasiveness.</p> Signup and view all the answers

<p>It decreases the working distance to 0.14 mm.</p> Signup and view all the answers

<p>The resolution increases, allowing for about 140,000 lines to an inch.</p> Signup and view all the answers

<p>It reduces light loss from reflection and minimizes distortion from diffraction.</p> Signup and view all the answers

<p>N.A. = n sin u = n sin θ</p> Signup and view all the answers

<p>A wider pencil of light increases the resolving power of the microscope.</p> Signup and view all the answers

<p>The shorter the wavelength, the finer the detail that can be resolved.</p> Signup and view all the answers

<p>RP = 5300 Å / (2 * 1.00) = 2650 Å.</p> Signup and view all the answers

<p>If the back lens is filled with light, the objective operates with maximum efficiency.</p> Signup and view all the answers

<p>The finest detail is determined by the wavelength and numerical aperture.</p> Signup and view all the answers

<p>Oil immersion lenses enhance resolution by matching the refractive index of the immersion fluid to glass.</p> Signup and view all the answers

<p>Only lens paper should be used to clean microscope lenses.</p> Signup and view all the answers

<p>Blue violet (4000 to 5000 Å), green (5000 to 6000 Å), and red (6000 to 7000 Å).</p> Signup and view all the answers

<p>To gather light rays from the object, unite them into an image point, and magnify the image.</p> Signup and view all the answers

<p>Numerical aperture is a measure of the resolving power of an objective lens; a larger N.A. indicates greater resolving power.</p> Signup and view all the answers

<p>The structure of light limits the resolving power; details smaller than the shortest wavelength of visible light cannot be seen.</p> Signup and view all the answers

<p>The image appears as a bright disk surrounded by concentric dark and light rings.</p> Signup and view all the answers

<p>They merge into a single bright area that appears uniform in the center.</p> Signup and view all the answers

<p>Resolution is inversely proportional to the wavelength; shorter wavelengths provide better resolution.</p> Signup and view all the answers

<p>The wavelength (λ) of the light used for illumination and the numerical aperture of the objective.</p> Signup and view all the answers

<p>It allows for numerical apertures greater than 1.0, enhancing the resolving power.</p> Signup and view all the answers

<p>The depth of focus decreases with higher N.A. and magnification.</p> Signup and view all the answers

<p>Cedarwood oil increases the refractive index, allowing for a cone of light of about 134 degrees.</p> Signup and view all the answers

<p>It indicates the ability to resolve details as close as 1/100,000 in. (0.2 µ).</p> Signup and view all the answers

<p>It is the distance from the front lens of the objective to the object when in sharp focus.</p> Signup and view all the answers

<p>It produces a real image of the same size as a simple biconvex lens of that focal distance.</p> Signup and view all the answers

<p>It allows for greater numerical apertures, enhancing light capture and resolution.</p> Signup and view all the answers

<p>The depth of focus becomes shallower.</p> Signup and view all the answers

<p>Water (n = 1.33) and cedarwood oil (n = 1.51).</p> Signup and view all the answers

<p>It serves as the baseline reference for comparing other media's refractive indexes.</p> Signup and view all the answers

<p>A higher N.A. decreases the depth of focus, meaning high-power objectives need more precise focusing.</p> Signup and view all the answers

<p>It indicates that the lens produces a real image of the same size as that produced by a simple converging lens with a focal distance of 1/2 in. or 2 mm.</p> Signup and view all the answers

<p>It is the distance from the front lens of the objective to the object when the microscope is in sharp focus.</p> Signup and view all the answers

<p>The cover slip decreases the working distance and alters the focus due to its refractive index.</p> Signup and view all the answers

<p>It can be calculated by taking the reciprocal of the cover slip's index of refraction.</p> Signup and view all the answers

<p>It will be impossible to get the object in focus.</p> Signup and view all the answers

<p>The greater the refractive index, the more the object will appear raised.</p> Signup and view all the answers

<p>Due to their higher magnification and N.A., high-power objectives have a shallower depth of focus.</p> Signup and view all the answers

<p>The primary factor that determines N.A. is the angular aperture of the lens.</p> Signup and view all the answers

<p>Replacing air with immersion oil increases the numerical aperture, allowing more divergent rays to be refracted into the lens.</p> Signup and view all the answers

<p>The formula for calculating numerical aperture is $N.A = refractive , index , of , medium , \times , \frac{sin , angular , aperture}{2}$.</p> Signup and view all the answers

<p>The refractive index influences the resolving power by affecting how much light can be focused through the lens.</p> Signup and view all the answers

<p>The resolving power is directly proportional to the width of the pencil of light used for illumination.</p> Signup and view all the answers

<p>The working distance decreases as the numerical aperture increases.</p> Signup and view all the answers

<p>It is expressed as $\sqrt{N.A.} = n , sin , u = n , sin , \theta$.</p> Signup and view all the answers

<p>The finest detail is determined by the wavelength of light divided by the numerical aperture, expressed as $rac{w.l.}{N.A.}$.</p> Signup and view all the answers