FOURIER TRANSFORM INFRA-RED SPECTROMETERS

Question 1

Which of the following is not true about Fourier Transform Infrared (FTIR) spectrometer?
a) It is of non-dispersive type
b) It is useful where repetitive analysis is required
c) Size has been reduced over the years
d) Size has increased over the years

Answer 1

d) Size has increased over the years

Question 2

In the most widely used beam splitter, a thin film of ________ is sandwiched between two plates of low refractive index solid. Fill the blank with a suitable option.
a) Mylar
b) Silicon carbide
c) Ferrous oxide
d) Silver chloride

Answer 2

a) Mylar

Question 3

Which of the following is not the function of the drive mechanism in Fourier Transform Infrared Spectrophotometer?
a) Movement of mirror to obtain a satisfactory interferogram
b) Acquire a good interferogram pattern
c) Allow 50% of the beam to pass
d) Keep the speed of the moving mirror constant

Answer 3

c) Allow 50% of the beam to pass

Question 4

Only pyroelectric transducer or pyroelectric crystals are used as detectors in Fourier Transform Infrared Spectrophotometer (FTIR). What is the main reason for other types of thermal detectors are not being used in FTIR spectrophotometer?
a) Less accuracy
b) Slower response
c) Less precision
d) Less sensitivity

Answer 4

b) Slower response

Question 5

Which of the following is not the advantage of Fourier Transform Spectrometers?
a) Signal to noise ratio is high
b) Information could be obtained on all frequencies
c) Retrieval of data is possible
d) Easy to maintain

Answer 5

d) Easy to maintain

Question 6

Which of the following has to be computed to determine transmittance and absorbance at various frequencies?
a) Ratio of signal and noise
b) Ratio of sample and reference spectra
c) Sample spectra
d) Reference spectra

Answer 6

b) Ratio of sample and reference spectra

Question 7

Computer accepts analog signals directly.
a) True
b) False

Answer 7

b) False

Question 8

Which of the following is the reference that is generally used in FTIR interferometer?
a) Air
b) NaCl solution
c) Alcohol
d) Base solution

Answer 8

a) Air

Question 9

In Michelson Interferometer, if the reflected and transmitted beams are in phase at the beam splitter, then maximum intensity will reach the detector.
a) True
b) False

Answer 9

a) True

Question 10

In Michelson’s interferometer, the frequency of the detector output can be determined by translating the _________ of movable mirror and the ___________ of monochromatic radiation.
a) Velocity, wavelength
b) Thickness, intensity
c) Length, velocity
d) Angle, intensity

Answer 10

a) Velocity, wavelength

Question 11

In Michelson’s interferometer, the __________ of the detector output will depend upon the intensity of incoming radiation.
a) Velocity
b) Frequency
c) Amplitude
d) Phase

Answer 11

c) Amplitude

Question 12

Why is the computer necessary in Fourier Transform Spectrometer?
a) To display the detector output
b) To process the detector output
c) To determine the amplitude
d) To determine the frequency

Answer 12

b) To process the detector output