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QUIZ INSTRUMENTATION, Assignments of Chemical Instrumentation and Analysis

LaGrange CollegeChemical Instrumentation and Analysis

ELECTROPHORESIS techniques used for separation of biomolecules

Typology: Assignments

2019/2020

Uploaded on 06/23/2020

divya-tripathy
divya-tripathy 🇮🇳

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1. Which part of the compound microscope helps in gathering and focusing light rays on the
specimen to be viewed?
a) Eyepiece lens
b) Objective lens
c) Condenser lens
d) Magnifying lens
View Answer
Answer: c
Explanation: Compound microscope contains three separate lens systems. The condenser lens is
placed between the light source and the specimen and it gathers and focuses the light rays in the
plane of the microscopic field to view the specimen.
2. What is the minimum distance for the eye to focus any object?
a) 11 cm
b) 25 cm
c) 32 cm
d) 4 2 cm
View Answer
Answer: b
Explanation: The eye cannot focus on objects brought closer to it less than 25 cm; this is,
accordingly the distance of maximal effective magnification. An object must also subtend an
angle at the eye of 1 degree or greater.
3. Resolving power of a microscope is a function of____________
a) Wavelength of light used
b) Numerical aperture of lens system
c) Refractive index
d) Wavelength of light used and numerical aperture of lens system
View Answer
Answer: d
Explanation: The ability of a microscope to distinguish two adjacent points as distinct and
separate is known as resolving power. Resolving power is a function of wavelength of light used
and the numerical aperture (NA) of the lens system.NA refers to the refractive index of the
medium multiplied with the sine value of the half-aperture angle.
4. The greatest resolution in light microscopy can be obtained with ___________
a) Longest wavelength of visible light used
b) An objective with minimum numerical aperture
c) Shortest wavelength of visible light used
d) Shortest wavelength of visible light used and an objective with the maximum numerical
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  1. Which part of the compound microscope helps in gathering and focusing light rays on the specimen to be viewed? a) Eyepiece lens b) Objective lens c) Condenser lens d) Magnifying lens View Answer Answer: c Explanation: Compound microscope contains three separate lens systems. The condenser lens is placed between the light source and the specimen and it gathers and focuses the light rays in the plane of the microscopic field to view the specimen.
  2. What is the minimum distance for the eye to focus any object? a) 11 cm b) 25 cm c) 32 cm d) 4 2 cm View Answer Answer: b Explanation: The eye cannot focus on objects brought closer to it less than 25 cm; this is, accordingly the distance of maximal effective magnification. An object must also subtend an angle at the eye of 1 degree or greater.
  3. Resolving power of a microscope is a function of____________ a) Wavelength of light used b) Numerical aperture of lens system c) Refractive index d) Wavelength of light used and numerical aperture of lens system View Answer Answer: d Explanation: The ability of a microscope to distinguish two adjacent points as distinct and separate is known as resolving power. Resolving power is a function of wavelength of light used and the numerical aperture (NA) of the lens system.NA refers to the refractive index of the medium multiplied with the sine value of the half-aperture angle.
  4. The greatest resolution in light microscopy can be obtained with ___________ a) Longest wavelength of visible light used b) An objective with minimum numerical aperture c) Shortest wavelength of visible light used d) Shortest wavelength of visible light used and an objective with the maximum numerical

aperture View Answer Answer: d Explanation: The relationship between numerical aperture (NA) and resolution is:- Resolution (d) = wavelength / 2(NA) Thus maximum resolution is obtained with the shortest wavelength of visible light and an objective with the maximum NA.

  1. Oil immersion objective lens has an NA value of____________ a) 0. b) 0. c) 1. d) 1. View Answer Answer: c Explanation: NA = refractive index * sine (half-aperture angle). The maximum NA for a dry objective is less than 1.0 as the refractive index of air is 1.The values of NA for oil immersion lens is slightly greater than 1.0 in the range of (1.2 to 1.4) as the refractive index of oil is 1.56.
  2. In fluorescence microscopy, which of the following performs the function of removing all light except the blue light? a) Exciter filter b) Barrier filter c) Dichroic mirror d) Mercury arc lamp View Answer Answer: a Explanation: In fluorescence microscopy, the function of the exciter filter is to remove all but the blue light; the barrier filter blocks out blue light and allows any other light emitted by the fluorescing specimen to pass through and reach the eye.
  3. Total Magnification is obtained by__________ a) Magnifying power of the objective lens b) Magnifying power of eyepiece c) Magnifying power of condenser lens d) Magnifying power of both the objective lens and eyepiece View Answer Answer: d Explanation: The total magnification is determined by multiplying the magnifying power of the
  1. The ratio of diameter of lenses to its focal length is referred as‐‐‐ a) Magnification b) resolution c) Numerical aperture d) none of the above
  2. ______ is the ability to reveal closely adjacent points as separate & distinct. a) Magnification b) resolution c) Numerical aperture d) none of the above
  3. If green light of wavelength 500nm objective with NA 1.4 is used, then the resolution will be‐‐‐‐‐ a)178X b)178nm c)178m d) None of the above
  4. ______ controls the intensity of light entering in microscope. a) Iris Diaphragm b) Mirror c) Condenser d) All of the above
  5. In _______ type of microscope, the field surrounding a specimen appears black, while the object itself is brightly illuminated. a) Compound microscope b)Phase contrast microscope c) Dark field microscope d) Fluorescence microscope
  1. Which of the following is NOT an advantage of using high pressure freezing? A. It can minimize artifacts prompted B. It can reduce ice-crystal damage C. Better preservation of antigens for immune-cytochemical studies can be achieved D. Large samples can be prepared
  2. Which of the following is the correct sequence of sample preparation before using the Transmission Electron Microscope? A. High pressure freezing→photo-polymerization→freeze substitution B. High pressure freezing→freeze substitution→photo-polymerization C. Photo-polymerization→high pressure freezing→freeze substitution D. Freeze substitution→high pressure freezing→photo- polymerization
    1. When using ultramicrotome for sectioning, what is the purpose of using glass knife? A. To trim the cutting edge of sample blocks so as to make it flat B. To section the specimens into thin slices C. To hold the sample blocks D. It allows us to monitor the process of sectioning
  3. With the use of ultramicrotome, we can section our sample into thickness of… A. 1 nm B. 10 nm C. 100 nm D. 1000 nm
    1. Why should we add water to the diamond cutting boat before sectioning? A. To remove dust from the boat B. To sharpen the diamond knife C. To prevent dehydration of sample after sectioning D. To facilitate the collection of sample slices
  4. Why TEM images have much higher resolution than images from light microscopes? A. TEM is much greater in size than light microscope B. Electrons traveling as waves have

wavelengths much shorter than visible light C. TEM can achieve greater magnification D. The fluorescent screen of TEM can generate high resolution images

  1. Which of the following is the correct pathway of electrons in the TEM? A. Anode → electromagnetic lens system → sample → fluorescent screen B. Anode → electromagnetic lens system → sample → electromagnetic lens system → fluorescent screen C. Cathode → electromagnetic lens system → sample → electromagnetic lens system → fluorescent screen D. Cathode → electromagnetic lens system → sample → fluorescent screen
  2. What should be done right after the TEM colume is shown to be evacuated? A. Insert the sample holder B. Further insert the sample holder C. Remove the dummy holder D. Shift the beam
  3. Before loading the sample, the following softwares have to be turned on, except... A. Electron gun tilt/shift B. TEM imaging and analysis C. Microscope user interface D. Digital micrograph
  4. For viewing which of the following would a TEM not be a good choice? A. Antigen B. Actin filament C. 3D external surface of mitochondria D. Ribosomes
  5. Which of these microscopes can be used to create high-resolution three-dimensional images of cells? A. differential interference contrast B. dark field C. phase-contrast D. confocal
  6. Confocal microscopes exhibit improved contrast and resolution by A. illumination of a large area of the specimen. B. blocking out stray light with an aperture located above the objective lens. C. use of light at longer wavelengths. D. use of ultraviolet light to illuminate the specimen.
  1. If the objective lenses of a microscope can be changed without losing focus on the specimen, they are said to be A. equifocal. B. totifocal. C. parfocal. D. optifocal.
  1. An instrument that magnifies slight differences in the refractive index of cell structures is called a (n) __________ microscope. A. phase-contrast B. electron C. fluorescence D. densitometric
  2. The instrument that produces a bright image of the specimen against a dark background is called a (n) __________ microscope. A. phase-contrast B. electron C. bright-field D. dark-field
  3. As the magnification of a series of objective lenses increases, the working distance A. increases. B. decreases. C. stays the same. D. cannot be predicted.

D. 1280 mm Answer