MMSC 407 Final Exam Questions and Verified
Answers
light Correct Answer: an energy source that can be characterized in terms of
wavelength, amplitude and frequency
-the visible spectrum
wavelength Correct Answer: the distance between waves
amplitude Correct Answer: the height of a wave
frequency Correct Answer: how many waves pass in one second (related to speed)
high energy waves Correct Answer: high frequency, very short and compact
wavelengths
-e.g. violet
low energy waves Correct Answer: low frequency, long wavelengths
-e.g. red
visible spectrum Correct Answer: the portion of the electromagnetic spectrum from
red (lowest energy) to violet (highest energy)
transmitted light Correct Answer: light that is able to pass through a solution
absorbed light Correct Answer: light that enters but does not leave a solution
inverse (fill in the blank) Correct Answer: light Transmittance (T) and absorbance
have a _____________________ relationship
-the more light that is absorbed, the less light there is left over to transmit
,beer's law Correct Answer: A=abc
-A= absorbance (calculated, no units)
-a= molar absorptivity: constant for a compound (L/mol*cm)
-b= light path through the solution: constant because same cuvette is used (cm)
-c= concentration of substance: value that is responsible for changes in absorbance
because its the only non-constant (mol/L)
directly (fill in the blank) Correct Answer: absorbance and concentration have a
_______________ proportional relationship
-the higher the absorbance in a sample, the higher the concentration of absorbing
substance was
spectrophotometer Correct Answer: -light source
-entrance slit: ensures no excess light is able to enter
-monochromator: isolates the particular wavelengths you want to measure
-exit slit
-sample contained (cuvette): determines the constant b (path of light through
solution) in beers law
-photodetector: converts light energy photons into electrical energy
-readout device: generates a voltage signal that measures how much light was
detected
glass filter (monochromator) Correct Answer: colored glass that absorbs and
transmits particular wavelengths of light
, -broad bandpass (50 nm)
-cheap
interference filter (monochromator) Correct Answer: a set of mirrored surfaces that
bounce light back and forth to produce constructive interference to produce desired
bandpass
-5-10 nm bandpass (pretty narrow)
glass prism (monochromator) Correct Answer: a curved spectrum is produced and
can be rotated to allow desired wavelength through the entrance slit
diffraction grating (monochromator) Correct Answer: parallel grooves that produce
a linear straight spectrum through bending of light
-best monochromator
-bandpass can be < 1 nm (VERY specific)
calibrator (standard) Correct Answer: a solution that is used in laboratory
instrument to establish a relationship between the instrument's signal readout and
the concentration of an analyte
-has a single known value (known concentration of analyte) to see if the instrument
is measuring properly
-used to calibrate machine
reference range calculation Correct Answer: mean +/- 2 standard deviations
establishing reference range Correct Answer: -evaluate 120 patient samples from a
healthy population
-population must represent the geographic area that is being served
Answers
light Correct Answer: an energy source that can be characterized in terms of
wavelength, amplitude and frequency
-the visible spectrum
wavelength Correct Answer: the distance between waves
amplitude Correct Answer: the height of a wave
frequency Correct Answer: how many waves pass in one second (related to speed)
high energy waves Correct Answer: high frequency, very short and compact
wavelengths
-e.g. violet
low energy waves Correct Answer: low frequency, long wavelengths
-e.g. red
visible spectrum Correct Answer: the portion of the electromagnetic spectrum from
red (lowest energy) to violet (highest energy)
transmitted light Correct Answer: light that is able to pass through a solution
absorbed light Correct Answer: light that enters but does not leave a solution
inverse (fill in the blank) Correct Answer: light Transmittance (T) and absorbance
have a _____________________ relationship
-the more light that is absorbed, the less light there is left over to transmit
,beer's law Correct Answer: A=abc
-A= absorbance (calculated, no units)
-a= molar absorptivity: constant for a compound (L/mol*cm)
-b= light path through the solution: constant because same cuvette is used (cm)
-c= concentration of substance: value that is responsible for changes in absorbance
because its the only non-constant (mol/L)
directly (fill in the blank) Correct Answer: absorbance and concentration have a
_______________ proportional relationship
-the higher the absorbance in a sample, the higher the concentration of absorbing
substance was
spectrophotometer Correct Answer: -light source
-entrance slit: ensures no excess light is able to enter
-monochromator: isolates the particular wavelengths you want to measure
-exit slit
-sample contained (cuvette): determines the constant b (path of light through
solution) in beers law
-photodetector: converts light energy photons into electrical energy
-readout device: generates a voltage signal that measures how much light was
detected
glass filter (monochromator) Correct Answer: colored glass that absorbs and
transmits particular wavelengths of light
, -broad bandpass (50 nm)
-cheap
interference filter (monochromator) Correct Answer: a set of mirrored surfaces that
bounce light back and forth to produce constructive interference to produce desired
bandpass
-5-10 nm bandpass (pretty narrow)
glass prism (monochromator) Correct Answer: a curved spectrum is produced and
can be rotated to allow desired wavelength through the entrance slit
diffraction grating (monochromator) Correct Answer: parallel grooves that produce
a linear straight spectrum through bending of light
-best monochromator
-bandpass can be < 1 nm (VERY specific)
calibrator (standard) Correct Answer: a solution that is used in laboratory
instrument to establish a relationship between the instrument's signal readout and
the concentration of an analyte
-has a single known value (known concentration of analyte) to see if the instrument
is measuring properly
-used to calibrate machine
reference range calculation Correct Answer: mean +/- 2 standard deviations
establishing reference range Correct Answer: -evaluate 120 patient samples from a
healthy population
-population must represent the geographic area that is being served
