Midterm exams I
Optical Microscopy
1. Spectrum of the visible light (blue, green, and red light)
2. Give a definition of absorption, refraction, dispersion and diffraction of the light.
3. Give a definition of the refraction index
4. Give a definition of the focal point and focal plane.
5. What is magnification power of the lens (write an expression).
6. Describe the difference between magnifying lens and compound microscope.
7. What is the Abbe condenser?
8. Describe Dark-field Microscopy
9. Give a definition of a plane wave (write an expression).
10. Describe the principles of operation the confocal optical microscope
11. Describe the field in the focal plane
12. Give a definition f the numerical aperture
13. Describe the Rayleigh criterion of resolution in microscopy
14. Give a definition f the lateral and axial resolution in optical microscopy (write an
expression)
15. Describe contrast in reflection and transmission optical microscopies.
16. For a given optical microscope objective explain meanings of the numbers on the side
face of the objective.
17. Give a definition of the Fourier transform (write an expression)
18. Write an expression for Fourier transform of the step function
Raman Spectroscopy
1. What is a Raman phenomenon?
2. What information do you get from a Raman spectrum?
3. What is the vibrational frequency of a diatomic molecule?
4. Where would be Raman lines (in cm-1 ) for (1) diamond and (2) for helium?
5. Which molecule would have higher vibrational frequency: Fluorine (F2) or iodine
(I2)?
6. Why Raman spectra should be measured at very low laser power?
7. Why Raman lines of amorphous phase looks broad in comparison to lines of
crystalline phase of the same material.
8. How can you experimentally determine what Raman lines are associated with
hydrogen bonds in a chemical?
Infrared Spectroscopy
1. What is the main difference between Raman and Infrared spectroscopies?
2. How many vibrational modes are there in CO2 and H2O?
3. At what wavelength region you would expect to measure the infrared spectra?
4. How do we know what elements are present in sun’s atmosphere?
5. Why no laser is used to measure the Infrared spectra and laser must be used to measure
the Raman spectra? Both techniques give information about the vibrational modes of a
molecule.
6. What is zero point energy? Are the molecules always vibrating?
7. What is the difference between the infrared imaging (night vision system) and infrared
spectroscopy?