Title: E7 Quiz
Course: Lab Instruments I > Section: E7: Meetings 13,14,15

Quiz over the objectives for experiment set 7.

Q: Ultraviolet and visible light induce ______ transitions whereas infrared light induces ______ transitions.
- electronic; rotational
- electronic; vibrational
- vibrational; electronic
- vibrational; rotational
A: electronic; vibrational

Q: Choose the statement that is TRUE for the absorbance spectra of an analyte.
- The shape of its absorption spectra changes with analyte concentration.
- The intensities of its absorption spectrum change with analyte concentration.
- The wavelength of maximum absorbance changes with analyte concentration.
- All of these are true.
A: The intensities of its absorption spectrum change with analyte concentration.

Q: An increase in transmittance is related to a(n) ______ in analyte concentration and a(n) ______ in absorbance.
- increase; increase
- increase; decrease
- decrease; increase
- decrease; decrease
A: decrease; decrease

Q: According to Beer’s Law, absorbance is related to all of the following EXCEPT which one of the following?
- The inside diameter of the cuvette or cell
- The amount of analyte per volume of solution
- The volume of sample solution in the light path
- The inherent ability of a substance to absorb light
A: The volume of sample solution in the light path

Q: Which one of the following is NOT commonly used to narrow the bandwidth of the light source in a UV-Vis spectrophotometer?
- Absorption filter
- Interference filter
- Interferometer
- Monochromator
A: Interferometer

Q: Absorption of ultraviolet and visible light produces a continuous spectrum for large molecules and a line spectrum for small molecules.
- True
- False
A: False

Q: A tungsten filament lamp is a source of electromagnetic radiation in the ultraviolet region.
- True
- False
A: False

Q: High resolution in spectrometry is associated with a narrow bandwidth reaching the sample.
- True
- False
A: True

Q: Both a photomultiplier tube and photodiode are sensors that convert light into an electrical current.
- True
- False
A: True

Q: Which one of the following statements is FALSE?
- In double-beam instruments, the blank is measured at the same time as the sample at each wavelength of interest.
- In single-beam instruments, the blank is measured before the sample at each wavelength of interest.
- Double-beam instruments account for small intensity fluctuations of the light source over time.
- Single-beam instruments can be used in a scanning wavelength mode of operation.
A: In double-beam instruments, the blank is measured at the same time as the sample at each wavelength of interest.

Q: Plastic is acceptable as sample cell material for use in which one of the following types of spectrometry?
- Infrared
- Ultraviolet
- UV-Vis
- Visible
A: Visible

Q: Which type of instrument most commonly uses mathematics to convert an interference light pattern to a spectrum?
- Atomic emission spectrometer
- Fluorometer
- IR spectrometer
- UV-Vis spectrophotometer
A: IR spectrometer

Q: Which one of the following statements is FALSE?
- UV-Vis spectroscopy can be used to analyze atoms but IR spectrometry cannot.
- UV-Vis spectroscopy is generally much faster for producing an absorption spectrum than IR spectrometry.
- UV-Vis spectroscopy can only analyze liquid/solution samples whereas IR spectrometry can analyze solid, liquid, or gas samples.
- UV-Vis spectroscopy is more generally useful for quantitative analysis whereas IR spectrometry is more generally useful for qualitative analysis.
A: UV-Vis spectroscopy is generally much faster for producing an absorption spectrum than IR spectrometry.

Q: An excited state electron _____ energy when it moves back to ground state in the form of ______.
- absorbs; light
- releases: light
- absorbs; heat and/or light
- releases; heat and/or light
A: releases; heat and/or light

Q: Which one of the following statements is FALSE?
- Fluorescence occurs when a substance emits ultraviolet light.
- Fluorometry tends to suffer less from interference than UV-Vis spectroscopy.
- A fluorometer measures emission and UV-Vis spectrometer measures transmittance.
- Fluorometry is typically a more sensitive quantitative analysis technique than UV-Vis spectrometry.
A: Fluorescence occurs when a substance emits ultraviolet light.