Instrumental Analysis – Exam 1 Star Questions with Verified Answers – Principles, Devices, and Calculations Explained

Instrumental Analysis Exam 1 – Star questions with
verified answers
A grating reflects first order light at 500 nm. The difference in two
wavelengths that can be detected using this grating is 0.010 nm. What
is the resolution of this monochromator (note that resolution is a
unitless quantity)? Ans✓✓✓ 5000 (resolution = λ/delta(λ) = (500
nm)/(0.010 nm) = 5000)


Advantages of Lasers Ans✓✓✓ intense, monochromatic, pulsed or
continuous wave, coherent, small beam divergence


Amperometry is based on what principle?
a. Interaction with electromagnetic radiation
b. electrical properties
c. miscellaneous properties
d. separation and resolution Ans✓✓✓ b. electrical properties


An aqueous solution of a dye has a strong absorption with λmax = 464
nm. The color of the solution is...
a. green
b. colorless
c. purple
d. orange Ans✓✓✓ d. orange

,an ideal transducer has... Ans✓✓✓ a high sensitivity, a high signal-to-
noise ratio, and a constant response over a considerable range of
wavelengths


Analog-Domain Signals Ans✓✓✓ magnitude of one of the electrical
quantities, continuously variable magnitude - current, voltage, charge,
power


Atomic absorption spectroscopy is based on what principle?
a. Interaction with electromagnetic radiation
b. electrical properties
c. miscellaneous properties
d. separation and resolution Ans✓✓✓ a. Interaction with
electromagnetic radiation


Atomic emission spectroscopy is based on what principle?
a. Interaction with electromagnetic radiation
b. electrical properties
c. miscellaneous properties
d. separation and resolution Ans✓✓✓ a. Interaction with
electromagnetic radiation

,Basic, single-beam spectrophotometers like the Spectronic 20 use
simple phototubes for detecting electromagnetic ration in the visible
range. These are useful as transducers because at saturation potential
the current is ____ to the radiant power of light striking the cathode. At
the same time, one must consider that such detectors have a
measurable ____ that must be accounted for. Ans✓✓✓ proportional,
dark current


binary digits Ans✓✓✓ bits


binary numbers are based on Ans✓✓✓ powers of 2


Calculate the wavelength of radiation emitted by an LED made up of a
semiconducting material with band gap energy 2.8 eV
a. 2.8Å
b. 4.3308 Å
c. 5548.4 Å
d. 4430.8 Å Ans✓✓✓ d. 4430.8 Å


Capillary electrophoresis is based on what principle?
a. Interaction with electromagnetic radiation
b. electrical properties
c. miscellaneous properties
d. separation and resolution Ans✓✓✓ d. separation and resolution

, Charge transfer devices and photodiodes are often used in instruments
where there is simultaneous detection of a range of wavelengths of
light. For this type of detection, individual transducers are arranged in
two-dimensional ____ which detect light after it has been separated by
a polychromator. Ans✓✓✓ arrays


Circular dichroism is based on what principle?
a. Interaction with electromagnetic radiation
b. electrical properties
c. miscellaneous properties
d. separation and resolution Ans✓✓✓ a. Interaction with
electromagnetic radiation


color absorbed and observed at 380-420 nm Ans✓✓✓ absorbed =
violet, observed = green-yellow


color absorbed and observed at 420-440 nm Ans✓✓✓ absorbed =
violet-blue, observed = yellow


color absorbed and observed at 440-470 nm Ans✓✓✓ absorbed =
blue, observed = orange


color absorbed and observed at 470-500 nm Ans✓✓✓ absorbed =
blue-green, observed = red