INSTRUMENTAL ANALYSIS FINAL
EXAM QUESTIONS AND DETAILED
ANSWERS. EXPERT VERIFIED FOR
GUARANTEED PASS.
Refractive index - ANS measure of the interaction between EMR and matter
=c/v
fourier transform - ANS can be used to deconvolute a complex waveform into a sum of
simple sine and/or cosine waves
takes a time domain signal and converts it to the frequency domain
diffraction - ANS parallel beam of EMR is bent as it passes through narrow slit
refraction - ANS abrupt change in the direction when EMR passes between media with
different refractive index
Snell's law - ANS
reflection - ANS light bounces off a medium
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,photoelectric effect - ANS if the frequency of incident light is above a threshold, it can cause
electron to be emitted from a metal photocathode. these electrons generate a photocurrent
that can be measured
low ionization energy = low ___ - ANS frequency
____ is not energetic enough to overcome the work function - ANS low frequency light
Intensity is directly proportional to ___ - ANS photons/second
types of emission from shortest to longest wavelength - ANS gamma, x-ray, UV, visible, IR,
microwave, radio
radiation - ANS EMR produced when excited particles relax to a lower energy level
ways to excite particles - ANS heat, spark, plasma, high voltage, EMR, chemical reaction
(exothermic)
line spectrum - ANS derived from individual atoms in the gas phase
sharp lines with typical width pf ~10^-4Å
band spectra - ANS derived from gaseous radicals/small molecules
results from numerous vibrational and rotational energy levels that are superimposed on
ground state
continuum spectra - ANS ex. the spectrum of blackbody radiation
as heat increases, wavelength of maximum emission decreases
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, absorbance formula - ANS A = -log(T) = -log(I/Io) = ɛbc
radiation sources - ANS continuum source and line source
continuum source examples - ANS Tungsten filament bulb
D2 lamp (most common for UV region)
globar or nernst flower for IR
very narrow wires = high ___ = higher ___ = ___ - ANS resistance
power
heat
line source example - ANS hollow cathode lamp (most common for AA)
reflection grating formula - ANS nλ = d(sin i + sin r)
if you are given the value 2000 lines/mm, what is d? - ANS d = (1mm/2000lines) x (10^6
nm/1mm) = 500 nm/line
prefer large or small dispersion? - ANS large bc wavelengths are well separated
reciprocal linear dispersion - ANS Echellete and Echelle grating
don't want f too large, as this would reduce light gathering power
criteria for assessing quality of monochromator - ANS spectral purity
resolution (ability to separate adjacent wavelengths)
light gathering power
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
EXAM QUESTIONS AND DETAILED
ANSWERS. EXPERT VERIFIED FOR
GUARANTEED PASS.
Refractive index - ANS measure of the interaction between EMR and matter
=c/v
fourier transform - ANS can be used to deconvolute a complex waveform into a sum of
simple sine and/or cosine waves
takes a time domain signal and converts it to the frequency domain
diffraction - ANS parallel beam of EMR is bent as it passes through narrow slit
refraction - ANS abrupt change in the direction when EMR passes between media with
different refractive index
Snell's law - ANS
reflection - ANS light bounces off a medium
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,photoelectric effect - ANS if the frequency of incident light is above a threshold, it can cause
electron to be emitted from a metal photocathode. these electrons generate a photocurrent
that can be measured
low ionization energy = low ___ - ANS frequency
____ is not energetic enough to overcome the work function - ANS low frequency light
Intensity is directly proportional to ___ - ANS photons/second
types of emission from shortest to longest wavelength - ANS gamma, x-ray, UV, visible, IR,
microwave, radio
radiation - ANS EMR produced when excited particles relax to a lower energy level
ways to excite particles - ANS heat, spark, plasma, high voltage, EMR, chemical reaction
(exothermic)
line spectrum - ANS derived from individual atoms in the gas phase
sharp lines with typical width pf ~10^-4Å
band spectra - ANS derived from gaseous radicals/small molecules
results from numerous vibrational and rotational energy levels that are superimposed on
ground state
continuum spectra - ANS ex. the spectrum of blackbody radiation
as heat increases, wavelength of maximum emission decreases
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, absorbance formula - ANS A = -log(T) = -log(I/Io) = ɛbc
radiation sources - ANS continuum source and line source
continuum source examples - ANS Tungsten filament bulb
D2 lamp (most common for UV region)
globar or nernst flower for IR
very narrow wires = high ___ = higher ___ = ___ - ANS resistance
power
heat
line source example - ANS hollow cathode lamp (most common for AA)
reflection grating formula - ANS nλ = d(sin i + sin r)
if you are given the value 2000 lines/mm, what is d? - ANS d = (1mm/2000lines) x (10^6
nm/1mm) = 500 nm/line
prefer large or small dispersion? - ANS large bc wavelengths are well separated
reciprocal linear dispersion - ANS Echellete and Echelle grating
don't want f too large, as this would reduce light gathering power
criteria for assessing quality of monochromator - ANS spectral purity
resolution (ability to separate adjacent wavelengths)
light gathering power
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
