Spectroscopy Multiple Choice Questions
1. The region of electromagnetic spectrum for nuclear magnetic resonance is __________
A. Microwave
B. Radio frequency
C. Infrared
D. UV-rays
Answer: B
Explanation: The region of the electromagnetic spectrum for nuclear magnetic resonance is radio frequency.
2. Which of the following is an application of molecular spectroscopy?
A. Structural investigation
B. Basis of understanding of colors
C. Study of energetically excited reaction products
D. All of the mentioned
Answer: D
Explanation: The various applications of molecular spectroscopy are- Structural investigation, basis of understanding of colors and study of energetically excited reaction products.
3. Select the correct statement from the following option.
A. Spectroscopic methods require less time and more amount of sample than classical methods
B. Spectroscopic methods require more time and more amount of sample than classical methods
C. Spectroscopic methods require less time and less amount of sample than classical methods
D. Spectroscopic methods require more time and less amount of sample than classical methods
Answer: C
Explanation: Spectroscopic methods require less time and less amount of sample than classical methods (1 mg).
4. The transition zone for Raman spectra is __________
A. Between vibrational and rotational levels
B. Between electronic levels
C. Between magnetic levels of nuclei
D. Between magnetic levels of unpaired electrons
Answer: A
Explanation: The transition zone for Raman spectra is between vibrational and rotational levels. Raman spectroscopy is a spectroscopic technique used to observe vibrational, rotational, and other low-frequency modes in a system.
5. The different types of energies associated with a molecule are __________.
A. Electronic energy
B. Vibrational energy
C. Rotational energy
D. All of the mentioned
Answer: D
Explanation: The different types of energies associated with a molecule are electronic energy, vibrational energy, rotational energy and translational energy.
6. During the motion, if the centre of gravity of molecule changes, the molecule possess __________
A. Electronic energy
B. Rotational energy
C. Translational energy
D. Vibrational energy
Answer: C
Explanation: During the motion, if the centre of gravity of molecule changes, the molecule possess translational energy. Translational refers to the movement in horizontal or vertical direction.
7. The correct order of different types of energies is __________
A. Eel >> Evib >> Erot >> Etr
B. Eel >> Erot >> Evib >> Etr
C. Eel >> Evib >> Etr >> Erot
D. Etr >> Evib >> Erot >> Eel
Answer: A
Explanation: The correct order is: Eel >> Evib >> Erot >> Etr. Electronic energy is the highest whereas translational energy is the lowest.
8. The criteria for electronic spin resonance is ____________.
A. Periodic change in polarisability
B. Spin quantum number of nuclei > 0
C. Presence of unpaired electron in a molecule
D. Presence of chromophore in a molecule
Answer: C
Explanation: The criterion for electronic spin resonance is the presence of unpaired electron in a molecule. This spectroscopy is a method for studying materials with unpaired electrons.
9. The analysis of electromagnetic radiation scattered, absorbed or emitted by the molecule is called __________
A. Kaleidoscopy
B. Astronomy
C. Spectroscopy
D. Anatomy
Answer: C
Explanation: The analysis of electromagnetic radiation scattered, absorbed or emitted by the molecule is called spectroscopy. Astronomy is the study of celestial objects and processes the physics, chemistry, and evolution of such objects and processes. A kaleidoscope is an optical instrument, typically a cylinder with mirrors containing loose, colored objects such as beads or pebbles and bits of glass. Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts.
10. The energy level with lower energy is called __________
A. Ground state energy level
B. Initial state energy level
C. Excited state energy level
D. All of the mentioned
Answer: A
Explanation: The lower energy level is called the ground state and the higher energy level is called excited state. The excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has higher energy than the ground state.
11. Absorption spectrum results when an electron in an atom undergoes a transition from __________
A. Higher energy level to a lower one
B. Lower energy level to a higher one
C. Intermediate levels
D. All of the mentioned
Answer: B
Explanation: Absorption spectrum results when an electron in an atom undergoes a transition from lower energy level to a higher one.
12. The energy of a photon is given by __________
A. h/ν
B. ν/h
C. 1/hν
D. hν
Answer: D
Explanation: The energy of a photon is given by hν where ν is the frequency and h is plank constant.
13. Select the incorrect statement from the following option.
A. Emission spectrum results when an electron in an atom undergoes a transition from excited state to the ground state
B. In the emission spectrum, transition takes place with the emission of a photon of energy hν
C. In the emission spectrum, transition takes place with the absorption of a photon of energy hν
D. All of the mentioned
Answer: C
Explanation: In the emission spectrum, transition takes place with the emission of a photon of energy hν. All the other options are correct. Emission spectrum results when an electron in an atom undergoes a transition from excited state to the ground state.
14. The spectra can be broadly classified into two categories. They are __________
A. Atomic and molecular spectra
B. Atomic and electronic spectra
C. Molecular and electronic spectra
D. None of the mentioned
Answer: A
Explanation: The spectra can be broadly classified into two categories: atomic and molecular spectra. Atomic spectra are the spectrum of frequencies of electromagnetic radiation emitted or absorbed during transitions of electrons between energy levels within an atom. Molecular spectra arises from the transition of an electron between the molecular energy levels.
15. Select the correct statement from the following options.
A. Molecular spectra arises from the transition of an electron between the molecular energy levels
B. In molecular transitions, electronic, rotational and vibration transitions occurs
C. Molecular spectra is more complicated than atomic spectra
D. All of the mentioned
Answer: D
Explanation: Molecular spectra arises from the transition of an electron between the molecular energy levels. In molecular transitions, electronic, rotational and vibration transitions occurs and molecular spectra is more complicated than atomic spectra.
16. The necessary condition for absorption spectrum is that __________
A. hν should be greater than the energy difference
B. hν should be smaller than the energy difference
C. hν should be equal to the energy difference
D. none of the mentioned
Answer: C
Explanation: The necessary condition for absorption spectrum is that hν should be equal to the energy difference(ΔE = Ee – Eg).
17. The electronic spectra in the visible range span is __________
A. 25000-72000 cm-1
B. 25000-50000 cm-1
C. 12500-25000 cm-1
D. 15000-30000 cm-1
Answer: C
Explanation: The electronic spectra in the visible range span 12500-25000 cm-1 and in the UV region span 25000-72000 cm-1.
18. Which of the following transitions are of weak intensities and lie in the visible region?
A. n→n*
B. σ→σ*
C. π→π*
D. n→σ*
Answer: A
Explanation: n→n* transitions are of weak intensities and lie in the visible region.
19. Arrange the various electronic transitions in the order of increasing energy.
A. n→σ* < π→π* < n→π* < σ→σ*
B. n→π* < π→π* < n→σ* < σ→σ*
C. n→σ* < n→π* < π→π* < σ→σ*
D. σ→σ* < π→π* < n→π* < n→σ*
Answer: B
Explanation: The correct order is- n→π* < π→π* < n→σ* < σ→σ*.
20. What is the position of the band of alkanes?
A. 190 nm
B. 185 nm
C. 217 nm
D. 150 nm
Answer: D
Explanation: The position of the band of alkanes is ≈150 nm. Alkanes refer to any of the series of saturated hydrocarbons including methane, ethane, propane, and higher members.
21. Which of the following organic compound shows transition due to conjugation?
A. Alkenes
B. Saturated aliphatic ketones
C. Conjugated dienes
D. Alkanes
Answer: C
Explanation: Conjugated dienes shows the transitions of low energy and is due to conjugation.
22. Which of the following is not an auxochrome group?
A. –OH
B. –SH
C. –OR
D. –O2
Answer: D
Explanation: Auxochrome is the color enhancing group. –O2 is not an example of auxochrome. -OH, -SH and -OR are examples of auxochrome.
23. Which of the following shift leads to the decreased intensity of absorption?
A. Hypochromic
B. Hyperchromic
C. Hypsochromic
D. Bathochromic
Answer: A
Explanation: Hypochromic shift leads to the decreased intensity of absorption. Hypochromicity describes a material’s decreasing ability to absorb light. Hyperchromicity is the material’s increasing ability to absorb light.
24. Which of the following is an application of electronic spectroscopy?
A. Detection of impurities
B. Control of purification
C. Study of kinetics of the chemical reaction
D. All of the mentioned
Answer: D
Explanation: Detection of impurities, control of purification, study of the kinetics of the chemical reaction, determination of molecular weight and determination of unknown concentration are the applications of electronic spectroscopy.
25. What will be the absorbance if %T = 80?
A. 0.5
B. 0.05
C. 0.097
D. 0.97
Answer: C
Explanation: Absorbance (A. = log(1/T) = log(100/80) = 0.097
26. Which of the following is a limitation of the Lambert-Beer’s law?
A. Scattering of light due to particles
B. Fluorescence of sample
C. Non-monochromatic radiation
D. All of the mentioned
Answer: D
Explanation: Scattering of light due to particles, fluorescence of the sample and non-monochromatic radiation are some of the limitations of Lambert-Beer’s law. It relates the attenuation of light to the properties of the material through which the light is traveling.
27. Vibrational spectroscopy involves the transitions falling in the spectral range of ____________
A. 100-1000 cm-1
B. 300-3000 cm-1
C. 400-4000 cm-1
D. 500-5000 cm-1
Answer: C
Explanation: Vibrational spectroscopy involves the transitions falling in the spectral range of 400-4000 cm-1 (infrared region).
28. Which of the region of IR spectra appears between (1400-600) cm-1?
A. Functional group region
B. Fingerprint region
C. Low-frequency region
D. None of the mentioned
Answer: B
Explanation: Fingerprint region of IR spectra appears between (1400-600) cm-1.
29. Select the correct statement from the following option.
A. Infrared spectra can identify the unknown materials
B. It can determine the amount of components in a mixture
C. It can also determine the quality of a sample
D. All of the mentioned
Answer: D
Explanation: Infrared spectra can identify the unknown materials. It can determine the amount of components in a mixture and can also determine the quality of a sample.
30. Which of the following molecule have infrared active vibrations?
A. NO
B. CH4
C. H2
D. All of the above
Answer: A
Explanation: NO molecule have infrared active vibrations. Infrared spectra can identify unknown materials. It can determine the amount of components in a mixture and can also determine the quality of a sample.
31. Which of the following cannot show a vibrational absorption spectrum?
A. OCS
B. H2O
C. CO2
D. CH2 = CH2
Answer: D
Explanation: CH2 = CH2 cannot show vibrational absorption spectrum. OCS, H2O and CO2 can show a vibrational absorption spectrum.
32. Which of the following is not a type of bending molecular vibration?
A. Twisting
B. Stretching
C. Wagging
D. Rocking
Answer: B
Explanation: Stretching is not a type of bending molecular vibration. Twisting, wagging and rocking are types of bending molecular vibration.
33. What is the absorption frequency(cm-1) of –C=N functional group?
A. 3610-3640
B. 1690-1760
C. 1180-1360
D. 2850-2960
Answer: C
Explanation: The absorption frequency for –C=N group is 1180-1360 cm-1. Absorption spectroscopy refers to spectroscopic techniques that measure the absorption of radiation, as a function of frequency or wavelength, due to its interaction with a sample.
34. Presence of a functional group in a compound can be established by using _____________
A. Chromatography
B. IR spectroscopy
C. Mass spectroscopy
D. X-ray diffraction
Answer: B
Explanation: Presence of a functional group in a compound can be established by using IR spectroscopy. It is the spectroscopy that deals with the infrared region of the electromagnetic spectrum that is light with a longer wavelength and lower frequency than visible light.
35. Select the incorrect option from the following option.
A. IR spectroscopy helps in the determination of purity
B. IR spectroscopy helps in the determination of force constant from vibrational spectrum
C. IR spectroscopy helps in identifying an unknown compound
D. None of the mentioned
Answer: D
Explanation: All the options are correct. IR spectroscopy helps in the determination of purity, force constant from the vibrational spectrum and identifying an unknown compound.
36. Which of the following technique is used to determine the protein sequence?
A. X – ray crystallography
B. NMR spectroscopy
C. Atomic spectroscopy
D. Mass spectroscopy
Answer: D
Explanation: Mass spectroscopy is a technique that is used to determine the protein sequence. X–Ray crystallography, NMR spectroscopy, and atomic spectroscopy cannot be used for the determination of protein sequence. Mass spectroscopy can also be used in many other fields.
37. Which among the following is an analytical technique that measures the mass-to-charge ratio of ions?
A. Atomic spectroscopy
B. NMR spectroscopy
C. Infrared spectroscopy
D. Mass spectroscopy
Answer: D
Explanation: Mass spectroscopy is an analytical technique that measures the mass-to-charge ratio of ions. Atomic spectroscopy, infrared spectroscopy, and NMR spectroscopy do not measure the mass-to-charge ratio of ions.
38. Which of the following analytical technique can be used to identify a chemical substance by the sorting of gaseous ions in electric and magnetic fields according to their mass-to-charge ratios?
A. Raman spectroscopy
B. Atomic spectroscopy
C. NMR spectroscopy
D. Mass spectroscopy
Answer: D
Explanation: Mass spectroscopy is an analytical technique that can be used to identify a chemical substance by the sorting of gaseous ions in electric and magnetic fields according to their mass-to-charge ratios. Whereas, Raman spectroscopy, atomic spectroscopy, and NMR spectroscopy cannot be used to identify a chemical substance by the sorting of gaseous ions in electric and magnetic fields according to their mass-to-charge ratios.
39. Which of the following is not a component of mass spectrometric technique?
A. Ion source
B. Analyzer
C. Detector
D. X – ray source
Answer: D
Explanation: X – ray source is not a component of mass spectrometric technique. Whereas, Ion source, analyzer, and detector are the components of the mass spectrometric technique. In ion source, a beam of charged particles characteristic of the sample is produced.
40. Which component of the mass spectrometers separates the ion beams into its components?
A. Sample handling system
B. Ion source
C. Detector
D. Analyzer
Answer: D
Explanation: The component of the mass spectrometers that separates the ion beams into its components is called an analyzer. The detector collects or observes the separated ion beams.
41. Which component of the mass spectrometers produces a beam of charged particles characteristic of the sample?
A. Radiation source
B. Analyzer
C. Detector
D. Ion source/ Ionizer
Answer: D
Explanation: The component of the mass spectrometers that produces a beam of charged particles characteristic of the sample is known as Ion source/ Ionizer. The radiation source, analyzer, and detector do not produce a beam of charged particles characteristic of the sample.
42. ESI and MALDI belong to which of the following techniques?
A. Detection
B. Analysis
C. Acceleration
D. Ionization
Answer: D
Explanation: ESI and MALDI are the techniques for ionization step in mass spectrometry. ESI stands for Electrospray ionizer, and MALDI stands for Matrix-Assisted Laser Desorprion/Ionization. Both of the techniques generate ions in the gaseous phase.
43. Which of the following is not an ionization technique?
A. MALDI
B. ESI
C. FAB
D. HPLC
Answer: D
Explanation: HPLC is not an ionization technique. HPLC stands for High-Performance Liquid Chromatography. MALDI, ESI, and FAB are not ionization techniques. FAB is Fast Atom Bombardment.
44. Which of the following is a sample inlet technique?
A. MALDI
B. TOF
C. ESI
D. GC/HPLC
Answer: D
Explanation: GC/HPLC is a sample inlet technique in mass spectrometry. GC is Gas Chromatography and HPLC is High-Performance Liquid Chromatography. MALDI, TOF, and ESI are not sampling inlet techniques. TOF is Time Of Flight.
45. Which of the following statement is false for mass spectroscopy?
A. Mass spectroscopy is used to identify unknown compounds within a sample, and to elucidate the structure and chemical properties of different molecules
B. Particle are characterized by their mass to charge ratios (m/z) and relative abundances
C. This technique basically studies the effect of ionizing energy on molecules
D. This technique can be used on all state of matter
Answer: D
Explanation: A mass spectrum measures the masses within a sample. Particles are characterized by their mass to charge ratios (m/z) and relative abundances. This technique basically studies the effect of ionizing energy on molecules and is applied to pure samples as well as complex mixtures. This technique is only possible to perform in the gaseous state.
46. Which of the following main component of mass spectroscopy deal with resolving the ions into their characteristics mass components according to their mass-to-charge ratio?
A. Ion Source
B. Analyzer
C. Detector System
D. Analyzer tube
Answer: B
Explanation: The complete process involves the conversion of the sample into gaseous ions, with or without fragmentation, which is then characterized by their mass to charge ratios (m/z) by an analyser. Eventually, the second analyzer will analyse fragment the selected ions and detect the ions emerging from the last analyzer and measure their and relative abundances with the detector that converts the ions into electrical signals.
47. Who discovered the mass spectrometer?
A. Francis Aston
B. J. J Thomson
C. Ernest O. Lawrence
D. Walter Kaufmann
Answer: B
Explanation: The mass spectrometer was invented by JJ THOMSON. He performed a series of experiments in 1897 designed to study the nature of electric discharge in a high-vacuum cathode-ray tube. Further modified by F. W. Aston shortly after World War I. He constructs the first velocity focusing mass spectrograph which has mass resolving power of 130.
48. In which state of matter mass spectroscopy is being performed?
A. Solid
B. Liquid
C. Gaseous
D. Plasma
Answer: C
Explanation: In the mass spectrometric analysis of compounds is firstly done by production of gas phase ions of the compound, basically by electron ionization. This molecular ion undergoes fragmentation.
49. What are the main criteria on which mass spectrometer used for?
A. Composition in sample
B. Relative mass of atoms
C. Concentration of elements in the sample
D. Properties of sample
Answer: B
Explanation: A mass spectrometer generates multiple ions from the sample under investigation, it then separates them according to their specific mass-to-charge ratio (m/z) or we can say on relative mass of atoms, and then records the relative abundance of each ion type.
50. Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?
A. Alpha particles
B. Neutrons
C. Electrons
D. Protons
Answer: C
Explanation: In the mass spectrometer, the sample which is to be analysed is bombarded with electrons, which leads to the formation of the ions. The ions are sorted out by accelerating them through electric and magnetic field. A record of the number of different kinds of ions is called mass spectrum.
51. Separation of ions in mass spectrometer take place on the basis of which of the following?
A. Mass
B. Charge
C. Molecular weight
D. Mass to charge ratio
Answer: D
Explanation: Mass spectrometer separates ions on the basis of mass to charge ratio i.e. m/z. In the spectrum of a pure compound, the molecular ion, if present, appears at the highest value of m/z (followed by ions containing heavier isotopes) and gives the molecular mass of the compound. Most of the ions are singly charged. Hence, the mass to charge ratio is equal to the mass.
52. Which type of ionic species are allowed to pass through the slit and reach the collecting plate?
A. Negative ions of all masses
B. Positive ions of the specific mass
C. Negative ions of the specific mass
D. Positive ions of all masses
Answer: B
Explanation: Positive ions of specific mass pass through the slit and reach the collecting plate. The ion currents are measured using sensitive electrometer tube. The ions reaching the collecting plate are measured.
53. The gas burden from conventional LC flow rates creates nearly _____ times more gas than cryo-pumped vacuum system can handle.
A. 5
B. 10
C. 20
D. 40
Answer: C
Explanation: The gas burden from conventional LC flow rates creates nearly 20 times more gas than cryo-pumped vacuum system can handle.
54. Which of the following should be in a position to split the effluent?
A. Interface
B. Ion source
C. Makeup gas
D. Microbore
Answer: A
Explanation: Interface should be in a position to split the effluent. LC-MS is a very advantageous method.
55. Which of the following is the most commonly used interface?
A. Nebulizer
B. Chopper
C. Filter
D. Vapourising chamber
Answer: A
Explanation: Nebulizer is the most commonly used interface. The nebulizer gas and the make-up gas are introduced coaxially into the heated nebulization region.
56. Only ______ percent of the effluent of the liquid chromatography must be introduced in the mass spectrometer.
A. 1-2 %
B. 1-5 %
C. 1-20 %
D. 1-15 %
Answer: B
Explanation: Only 1-5 percent of the effluent of the liquid chromatography must be introduced in the mass spectrometer. Therefore, the total effluent must be split.
57. Which of the following is the normal nebuliser temperature used in LC mass spectrometry?
A. 50-100oC
B. 100-200oC
C. 125-150oC
D. 150-200oC
Answer: C
Explanation: 125-150oC is the normal nebuliser temperature used in LC mass spectrometry. It is suitable for a variety of applications.
58. The ions are focussed and de-clustered through which of the following regions?
A. Dry helium region
B. Wet oxygen region
C. Wet chlorine region
D. Dry nitrogen region
Answer: D
Explanation: The ions are focussed and de-clustered through a dry nitrogen region. It is then sent into the high vacuum analyser.
59. The ions are passed into the high vacuum analyser through which of the following?
A. Orifice
B. Nozzle
C. Nebulizer
D. Venturi tube
Answer: A
Explanation: The ions are sent into the high vacuum analyser through an orifice. It is then mass analysed.
60. Gas burden from conventional LC flow rates is which of the following?
A. 1ml/min of water produces 1.2 l/mm of gas
B. 1ml/min of water produces 2.4 l/mm of gas
C. 2ml/min of water produces 3.2 l/mm of gas
D. 1ml/min of water produces 4.2 l/mm of gas
Answer: A
Explanation: In LC-mass spectrometry, 1ml/min of water produces 1.2 l/mm of gas. This is the gas burden that conventional flow rates produced.
61. Which of the following is not a component of mass spectrometer?
A. Inlet system
B. Sweep generator
C. Ion transducer
D. Mass analyser
Answer: B
Explanation: Sweep generator is not a component of a mass spectrometer. It is a component of NMR spectrometer.
62. Which of the following can be introduced into the ionization chamber directly?
A. Solid samples with low vapour pressure
B. Solid samples with high vapour pressure
C. Liquid samples with low density
D. Liquid samples with high density
Answer: A
Explanation: Solid samples with low vapour pressure can be introduced into the ionization chamber directly.
63. Inlet system is also known as which of the following?
A. Initial system
B. Sample reservoir
C. Sample handling system
D. Element injection system
Answer: C
Explanation: Inlet system introduces the sample into the ion source. Hence, it is called a sample handling system
64. Which of the following is normally done to convert the sample into the gaseous state?
A. Sample is pressurized
B. Chemical reactions are made to occur
C. Sample is heated
D. Sample is cooled
Answer: C
Explanation: The sample must always be in the gaseous state. Hence, the liquid sample must be heated before introducing them into the ionization chamber.
65. Which of the following probes are used for the introduction of the sample?
A. Silica
B. Quartz
C. Graphite
D. Silver
Answer: A
Explanation: Solid samples with low vapour pressure are introduced into the entrance of the chamber. They are introduced using silica or platinum probe.
66. Which of the following is not a type of ionisation?
A. Field ionisation
B. Spontaneous ionisation
C. Spark ionisation
D. Chemical ionisation
Answer: B
Explanation: Spontaneous ionisation is not a type of ionisation. In mass spectrometer, ionisation is brought about by thermal or electrical energy.
67. Mass analyser is similar to which of the following in optical spectrometer?
A. Source
B. Monochromator
C. Detector
D. Sample
Answer: B
Explanation: Mass analyser is similar to monochromator in an optical spectrometer. It separates ions according to their mass/charge ratio.
68. Which of the following is not one of the types of mass analyser?
A. Magnetic sector analyser
B. Frequency sweep analyser
C. Double focussing spectrometer
D. Time of flight analyser
Answer: B
Explanation: Frequency sweep analyser is not a type of mass analyser. There are many devices available for mass analysis.
69. Which of the following is not a type of ion detector used in mass spectrometers?
A. Electron multiplier
B. Flame emission detector
C. Faraday cup collector
D. Photographic plates
Answer: B
Explanation: Flame emission detector is not a type of ion detector used in mass spectrometers. Ion detectors produce a current on the output side when there are ions on the input side.
70. Which of the following is used to inject liquid samples?
A. Hypodermic needle
B. Glass bulb
C. Capillary tube
D. Curvette
Answer: A
Explanation: Liquid samples are injected through hypodermic needles. It is vaporized at low pressure.
71. Under which of the following temperatures is the ionisation chamber maintained?
A. 100oC
B. 200oC
C. 300oC
D. 400oC
Answer: B
Explanation: The ionisation chamber is maintained at 200oC. It is also maintained at low pressure.
72. Given below is the block diagram of mass spectrometer. Identify the unmarked component.
A. Inlet system
B. Ionisation chamber
C. Vacuum system
D. Ion transducer
Answer: D
Explanation: The unmarked component is ion transducer. It will give current at the output at its output side when ions are present on the input side.
73. Which of the following is not a characteristic of nebulizers that are commonly used?
A. Low cost
B. Low uptake rate
C. High efficiency
D. High uptake rate
Answer: D
Explanation: Commonly used nebulizers have a low uptake rate. They also have low cost and high efficiency.
74. In glow discharge ion source, the sample is atomised by which of the following process?
A. Evaporation
B. Sputtering
C. Heating
D. Annealing
Answer: B
Explanation: In glow discharge ion source, the sample is atomised by the process of sputtering. It not only atomizes the sample but also provides means by which these atoms are ionized.
75. Which of the following is not a component of the time of flight analyser spectrometer?
A. Ion source
B. Field free separation region
C. Electron multiplication region
D. Photo tube
Answer: D
Explanation: Phototube is not a component of time of flight mass spectrometer. Time of flight mass analyser is a type of mass spectrometer.
76. Which of the following is not an advantage of mass spectrometer?
A. Simple
B. Rugged
C. High sensitivity
D. Unlimited mass range
Answer: C
Explanation: Time of flight mass spectrometers have limited sensitivity and resolution. They are simple and rugged.
77. If all the ions have the same kinetic energy how are their masses related to their velocities?
A. Mass and velocity are equal
B. Mass and velocity are not related
C. Mass and velocity are directly proportional
D. Mass and velocity are inversely proportional
Answer: D
Explanation: If all the ions have the same kinetic energy, mass and velocity are inversely proportional. This is used in the separation of ions.
78. Which of the following is true about time of flight analyser spectrometers?
A. Lighter particles arrive at the detector earlier
B. Heavier particle arrive at the detector earlier
C. Lighter and heavier particles arrive together at the detector
D. Lighter particles do not reach the detector
Answer: A
Explanation: Lighter particles arrive at the detector earlier than the heavier particles. The time difference is used to separate the electrons according to their mass.
79. In the time of flight mass spectrometer, ions are formed by which of the following methods?
A. Pulsed ionization method
B. Acceleration method
C. Dynamic method
D. Ion excitation method
Answer: A
Explanation: In the time of flight mass spectrometer, ions are formed by pulsed ionisation method. It is a type of Mass Spectrometer.
80. The evacuated tube is also known as which of the following?
A. Pulse tube
B. Detector tube
C. Drift tube
D. Acceleration tube
Answer: C
Explanation: The evacuated tube is also known as a drift tube. The electrons move from source to detector through the tube.
81. The current produced by ions arriving at the collector necessitates the use of which of the following?
A. Wide band amplifier
B. Narrow band amplifier
C. Wide band filter
D. Narrow band filter
Answer: A
Explanation: The current produced by ions arriving at the collector has very short duration. Hence, it necessitates the use of wide band amplifier.
82. Which of the following is an ion optic device in which ions pass through a mirror and their flight is reversed?
A. Reversal device
B. Reflectron
C. Mirror arrangement
D. Separation chamber
Answer: B
Explanation: Reflectron is an ion optic device in which ions pass through a mirror and their flight is reversed. It is used in time of flight mass spectrometer.
83. Which of the following statements about mass spectrometers are not true?
A. Time of flight mass spectrometer has the ability to record the entire mass spectrum at a time
B. Time of flight mass spectrometers have poor resolution
C. Conventional spectrometer detects only one peak at a time
D. All spectrometers have the ability to record the entire mass spectrum at a time
Answer: D
Explanation: Conventional spectrometer detects only one peak at a time. Time of flight mass spectrometer has the ability to record the entire mass spectrum at a time.
84. In X-ray spectrometers, the specimen or the sample is placed after which of the following components?
A. X-ray tube
B. Monochromator
C. Collimator
D. Detector
Answer: A
Explanation: In X-ray spectrometers, the specimen or the sample is placed after the X-ray tube. The X-ray tube is the source of the X-ray.
85. Which of the following components are used to generate X-rays?
A. Meyer tube
B. West tube
C. Anger tube
D. Coolidge tube
Answer: d
Explanation: Coolidge tube is used to generate X-rays. It is the source of X-rays. Coolidge tube requires stabilised current and high voltage.
86. Using which of the following components is the generated x-rays focussed upon the specimen?
A. X-ray tube
B. Monochromator
C. Collimator
D. Detector
Answer: C
Explanation: Collimator is used to focus the generated x-rays upon the specimen. The collimator is in between the specimen under analysis and the Coolidge tube.
87. The cathode in the Coolidge tube is made of which of the following elements?
A. Quartz
B. Iron
C. Tungsten
D. Barium
Answer: C
Explanation: The cathode in the Coolidge tube is made of tungsten. The anode is made of copper.
88. Which of the following is not a target metal used in the Coolidge tube?
A. Rhodium
B. Cobalt
C. Gold
D. Silver
Answer: C
Explanation: Gold is not used as a target metal in the Coolidge tube. The other target metals are copper, molybdenum and chromium.
89. How can the resolution of the collimator be increased?
A. By reducing the separation between the metal plates of the collimator
B. By increasing the separation between the metal plates of the collimator
C. By increasing the number of metal plates
D. By decreasing the number of metal plates
Answer: A
Explanation: The resolution of the collimator can be increased by reducing the separation between the metal plates of the collimator. Collimator has a series of closely spaced parallel metal plates.
90. When x-rays emitted from molybdenum are allowed to pass through a zirconium filter, which of the following occurs?
A. It absorbs radiation of shorter wavelength
B. It absorbs radiation of longer wavelength
C. It allows radiation of shorter wavelength to pass through
D. It allows radiation in a particular band to pass through
Answer: B
Explanation: When x-rays emitted from molybdenum are allowed to pass through a zirconium filter, it absorbs radiation of shorter wavelength. It allows radiation of a stronger wavelength to pass through.
91. Which of the following crystals are not suited for x-ray grating?
A. Topaz
B. Lithium fluoride
C. Calcium fluoride
D. Sodium fluoride
Answer: D
Explanation: The crystal which is not suited for x-ray grating is sodium fluoride. Other crystals which are suitable for x-ray grating are gypsum and sodium chloride.
92. Given below is the block diagram of X-ray spectrometer. Identify the unmarked component.
A. Filter
B. Monochromator
C. Specimen
D. Amplifier
Answer: C
Explanation: The unmarked component is specimen. It is the sample under analysis.
93. The x-rays generated come out of the Coolidge tube through which of the following?
A. Beryllium window
B. Tungsten window
C. Collimator
D. Target material
Answer: A
Explanation: The x-rays generated come out of the Coolidge tube through a beryllium window. Some energy is lost as heat.
94. Which of the following is the principle of Atomic Absorption Spectroscopy?
A. Radiation is absorbed by non-excited atoms in vapour state and are excited to higher states
B. Medium absorbs radiation and transmitted radiation is measured
C. Colour is measured
D. Colour is simply observed
Answer: A
Explanation: Atoms in gaseous state absorb the radiation and are excited to a higher state. Since the higher state is unstable the atom returns the ground state with the emission of radiation which is measured.
95. In Atomic Absorption Spectroscopy, which of the following is the generally used radiation source?
A. Tungsten lamp
B. Xenon mercury arc lamp
C. Hydrogen or deuterium discharge lamp
D. Hollow cathode lamp
Answer: D
Explanation: Hollow cathode lamp is the source used in Atomic Absorption Spectroscopy. It emits stable and intense radiation.
96. In Atomic Absorption Spectroscopy, with what material is the cathode in Hollow cathode lamp constructed?
A. Tungsten
B. Quartz
C. Element to be investigated
D. Aluminium
Answer: C
Explanation: The cathode in Hollow cathode lamp is constructed of the element to be investigated. The anode is made of tungsten.
97. How can the intensity of radiation be increased in Hollow cathode lamp?
A. Addition of non-conductive protective shield of mica
B. Addition of nitrogen to neon or argon in the lamp
C. Increasing the pressure of the filling gas
D. Changing the metal of the anode
Answer: A
Explanation: The intensity of radiation is increased in Hollow cathode lamp by the addition of a non-conductive protective shield of mica. The protective shield can be made of glass too.
98. Which of the following is the function of the chopper in Atomic Absorption Spectroscopy?
A. To split the beam into two
B. To break the steady light into a pulsating light
C. To filter unwanted components
D. To reduce the sample into atomic state
Answer: B
Explanation: The function of the chopper in Atomic Absorption Spectroscopy is to break the steady light into pulsating light. It is a rotating wheel placed between the flame and the source.
99. Which of the following is the function of the Flame or Emission system in Atomic Absorption Spectroscopy?
A. To split the beam into two
B. To break the steady light into pulsating light
C. To filter unwanted components
D. To reduce the sample into atomic state
Answer: D
Explanation: The function of Flame or Emission system in Atomic Absorption Spectroscopy is to reduce the sample into atomic state. In Atomic Absorption Spectroscopy, the production of atomic vapour by flame is the most important phase.
100. Which of the following is not a component of the emission system in Flame photometer?
A. Burner
B. Atomiser
C. Fuel gases and their regulation
D. Chopper
Answer: D
Explanation: Chopper is not a component of the emission system in Flame photometer. The parts of flame photometer are burner, atomiser, fuel gases and their regulation and flame.
101. Which of the following is the function of the atomiser in the emission system of Atomic Absorption Spectroscopy?
A. To split the beam into two
B. To break the steady light into pulsating light
C. To break large mass of liquid into small drops
D. To reduce the sample into atomic state
Answer: C
Explanation: The function of atomiser in the emission system of Atomic Absorption Spectroscopy is to break large mass of liquid into small drops. It also introduces liquid sample into the flame at a stable rate.
102. Which of the following is not the requirement of a good flame in flame photometer?
A. Liquid sample must be evaporated to form solid residue
B. Solid residue must decompose to form atoms
C. Atoms must be produced such that they have the ability to get excited to higher states
D. Atoms must be produced such that they are in stable state
Answer: D
Explanation: Atoms must be produced such that they have the ability to get excited to higher states. These atoms in higher states return to ground state with the emission of photons.
103. Which of the following options explains the process of ‘sputtering’ that occurs in Hollow Cathode Lamp?
A. Positive ions collide with cathode surface and metal atoms from cathode are ejected
B. Negative ions collide with cathode surface and metal atoms from anode are ejected
C. Positive ions collide with negative ions and metal atoms from anode are ejected
D. Positive ions collide with negative ions and photons are ejected
Answer: A
Explanation: When potential is applied across the electrode, the gas filled in tube ionises and flow of current occurs. Positive ions collide with negatively charged cathode surface and metal atoms from a cathode are ejected.
104. At what pressure should the gases in the sealed tube be maintained in the Hollow cathode lamp?
A. 1 to 5 torr
B. 20 to 30 torr
C. 40 to 50 torr
D. 50 to 55 torr
Answer: A
Explanation: It consists of a cylindrical cathode and an anode made of tungsten. The tube is sealed and neon and argon are filled at a pressure of 1 to 5 torr.
105. The diagram show below is the picture of Hollow cathode lamp. Identify the unmarked component.
A. Glass tube
B. Quartz window
C. Non- conducting glass
D. Mica shield
Answer: B
Explanation: The unmarked portion is Quartz window. The window can be made of quartz or borosilicate glass.
106. A basic X-ray source includes which of the following components?
A. Large target anode
B. Large target cathode
C. Small target anode
D. Small target cathode
Answer: A
Explanation: A basic X-ray source includes a large target anode. It also has a heating element.
107. The anode is held at __________ positive potential and the filament is held at ____________ potential.
A. High, ground
B. Ground, high
C. Low, high
D. High, low
Answer: A
Explanation: The anode is held at high potential and the filament is held at ground potential. Electrons are accelerated from the filament.
108. Which of the following is one of the most commonly used anode material?
A. Carbon
B. Tungsten
C. Magnesium
D. Cesium
Answer: C
Explanation: Magnesium is one of the most commonly used anode material. Aluminium is also commonly used.
109. Which is the most intense line in the X-ray spectrum?
A. Kα1
B. Kα2
C. Kα12
D. Kα22
Answer: C
Explanation: Kα12 is the most intense line in the X-ray spectrum. Different lines have specific energies.
110. Which of the following must be used with the X-ray source to have high energy resolution?
A. Chopper
B. Vacuum chamber
C. Accelerator
D. Monochromator
Answer: D
Explanation: Monochromator must be used with the X-ray source to have high energy resolution. It will also remove the satellite lines.
111. Double-pass cylindrical mirror energy analyser has how many mirrors?
A. One
B. Two
C. Three
D. Four
Answer: B
Explanation: Double-pass cylindrical mirror energy analyser has two mirrors. It is commonly used in electron spectroscopy.
112. In spherical sector analyser, __________ is detected and plotted as a function of energy.
A. Mass
B. Charge
C. Number of electrons striking the detector
D. Mass to charge ratio
Answer: C
Explanation: In spherical sector analyser, the number of electrons striking the detector is detected and plotted as a function of energy. It is detected for a constant potential.
113. Which of the following is the most commonly used detector in ESCA and AES?
A. Electron multiplier
B. Dynodes
C. Photovoltaic cell
D. Photomultiplier
Answer: A
Explanation: Electron multiplier is the most commonly used detectors in ESCA and AES. It is similar to photomultiplier.
114. Electron detector has a _______ doped glass tube with a secondary semiconducting coating.
A. Quartz
B. Silica
C. Lead
D. Cesium
Answer: C
Explanation: Electron detector has a lead doped glass tube with a secondary semiconducting coating. It has a high secondary electron shield.
115. The output of the multiplier is fed to which of the following immediately?
A. Pulse amplifier discriminator
B. DAC
C. ADC
D. Multichannel analyser
Answer: A
Explanation: The output of the multiplier is fed to pulse amplifier discriminator. It is then fed to a multichannel analyser.
116. Which of the following is the ideal vacuum for electron spectrometers?
A. 10-6 torr
B. 10-7 torr
C. 10-8 torr
D. 10-9 torr
Answer: A
Explanation: 10-6 torr is the ideal vacuum for electron spectrometers. Vacuum below 10-6 torr can also be used.
117. Which of the following is the most commonly used magnetic shielding?
A. Helmholtz coils
B. Ferro-magnetic shielding
C. Faraday shield
D. Magnetometer probe
Answer: B
Explanation: Ferro-magnetic shielding is the most commonly used magnetic shielding. Helmholtz coil can be used as alternative.
118. Charging effect can be suppressed by supplying flood of electrons having which of the following?
A. Uniform low energy
B. Uniform low mass
C. Uniform high energy
D. Uniform high mass
Answer: A
Explanation: Charging effect can be suppressed by supplying flood of electrons having uniform low energy. It also results in attainment of additional useful information.
119. In Ion spectroscopy, the primary ion is usually which of the following?
A. Inert gas ion
B. Halogen ion
C. Oxygen group gas ion
D. Hydrogen
Answer: A
Explanation: In Ion spectroscopy, the primary ion is usually an inert gas ion. When primary ion having particular kinetic energy is incident on a surface certain phenomena can occur.
120. The kinetic energy of the primary ion should be in which of the following range?
A. 0.1-4 keV
B. 0.2-1 keV
C. 0.4-2 keV
D. 0.3-5 keV
Answer: D
Explanation: The kinetic energy of the primary ion should be 0.3-5 keV. These primary ions are made incident on the surface.
121. If the primary ion is elastically scattered, the kinetic energy of the reflected primary ion will depend on which of the following?
A. Charge of the primary ion
B. Charge of the surface ion
C. Mass of the surface ion
D. Number of surface ions
Answer: C
Explanation: If the primary ion is elastically scattered, the kinetic energy of the reflected primary ion will depend on the mass of the surface ion. The reflected ion is measured by ISS.
122. Which of the following causes the phenomena of sputtering?
A. Primary ion gets embedded in the solid
B. Primary ion is elastically scattered
C. Primary ion is reflected
D. Primary ion is refracted
Answer: A
Explanation: Primary ion may penetrate through a few layers of the surface and get embedded in the solid. This causes scattering.
123. Which of the following is the energy range of ISS (Ion Scattering Spectroscopy)?
A. 1 keV
B. 2 keV
C. 4 keV
D. 8 keV
Answer: A
Explanation: The energy range of the ISS is 1 keV.
124. Which of the following is the spectral range of SIMS (Secondary Ion Mass Spectroscopy)?
A. 0-10 amu
B. 0-100 amu
C. 0-500 amu
D. 0-1000 amu
Answer: C
Explanation: The spectral range of SIMS is 0-500 amu.
125. Which of the following is denotes the absolute quantitative analysis of SIMS?
A. 30%
B. 70%
C. 50%
D. Not possible
Answer: D
Explanation: Absolute quantitative analysis is not possible in SIMS. It is possible in ISS.
126. Which of the following is the amount of matrix effect that occurs in SIMS?
A. Very low
B. Low
C. Some
D. Severe
Answer: D
Explanation: Severe matrix effects occur in SIMS. Some matrix effects occur in ISS.
127. Which of the following is the x-y resolution of ISS?
A. 1 µ
B. 10 µ
C. 100 µ
D. 1000 µ
Answer: C
Explanation: The x-y resolution of ISS is 100 µ. It has a poor x-y resolution.
128. Which of the following is the x-y resolution of SIMS?
A. 1 µ
B. 10 µ
C. 100 µ
D. 1000 µ
Answer: A
Explanation: The x-y resolution of SIMS is 1 µ. It has this resolution when used with ion microprobe.
129. 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: D
Explanation: FTIR is of non-dispersive type of instruments and is used for repetitive analysis. Initially, it was bulky and the cost was high and hence, it was limited to a special application. Now, the size has been reduced.
130. 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: A
Explanation: Generally, mylar is the thin film used in beam splitters. Beam splitter has to pass 50% of the radiation and reflect 50% of the radiation.
131. 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: C
Explanation: Drive mechanism does the functions specified in the other options. It the function of the beam splitter to allow 50% of the beam to pass through
132. 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: B
Explanation: Other thermal detectors are not employed due to slower response of the detectors. Pyroelectric transducers or pyroelectric crystals are chosen for their high speed, accuracy, precision, sensitivity and resolution.
133. 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: D
Explanation: The instrument is not easy to maintain and it is a disadvantage. The other disadvantage is that the cost is high.
134. 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: B
Explanation: The ratio of sample and reference spectra needs to be computed to determine transmittance and absorbance. First, reference interferogram is obtained and then the sample is obtained.
135. 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: A
Explanation: Air is generally used as the reference. It is scanned for about 20 to 30 times and the results are stored in a computer.
136. 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: A
Explanation: The frequency can be determined by translating the velocity of the movable mirror and the wavelength of monochromatic radiation. The reflected beam passes towards the movable mirror.
137. 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: C
Explanation: In Michelson’s interferometer, the amplitude of the detector output will depend upon the intensity of incoming radiation. If a movable mirror is moved uniformly, the output will be a sine wave.
138. 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: B
Explanation: The computer is necessary to process the output of the detector. The Fourier Transform of output is determined using software using computers.
139. Beer Lambert’s law gives the relation between which of the following?
A. Reflected radiation and concentration
B. Scattered radiation and concentration
C. Energy absorption and concentration
D. Energy absorption and reflected radiation
Answer: C
Explanation: Beer Lambert’s law gives the relation between Energy absorption and Concentration. It was proposed by Beer and Lambert.
140. In which of the following ways, absorption is related to transmittance?
A. Absorption is the logarithm of transmittance
B. Absorption is the reciprocal of transmittance
C. Absorption is the negative logarithm of transmittance
D. Absorption is a multiple of transmittance
Answer: C
Explanation: Transmittance is the ratio of the radiant power transmitted by a sample to the radiant power incident on the sample. Absorption is the negative logarithm of transmittance.
141. Which of the following is not a limitation of Beer Lambert’s law, which gives the relation between absorption, thickness and concentration?
A. Concentration must be lower
B. Radiation must have higher bandwidth
C. Radiation source must be monochromatic
D. Does not consider factors other than thickness and concentration that affect absorbance
Answer: B
Explanation: The law is derived assuming that the radiation is monochromatic. So, if bandwidth increases it will create deviation.
142. Beer’s law states that the intensity of light decreases with respect to ___________
A. Concentration
B. Distance
C. Composition
D. Volume
Answer: A
Explanation: Beer’s law states that the intensity of light decreases with the concentration of the medium. It was stated by Beer.
143. Lambert’s law states that the intensity of light decreases with respect to __________
A. Concentration
B. Distance
C. Composition
D. Volume
Answer: B
Explanation: Lambert’s law states that the intensity of light decreases with respect to the concentration of the medium. It was stated by Lambert.
144. The representation of Beer Lambert’s law is given as A = abc. If ‘b’ represents distance, ‘c’ represents concentration and ‘A’ represents absorption, what does ‘a’ represent?
A. Intensity
B. Transmittance
C. Absorptivity
D. Admittance
Answer: C
Explanation: ‘a’ represents the absorption constant. It is also known as absorptivity.
145. Which of the following is not true about Absorption spectroscopy?
A. It involves transmission
B. Scattering is kept minimum
C. Reflection is kept maximum
D. Intensity of radiation leaving the substance is an indication of a concentration
Answer: C
Explanation: In Absorption spectroscopy, reflection must also be kept minimum along with scattering. Amount of absorption depends on the number of molecules in the material.
146. Transmittance is given as T = P/Po. If Po is the power incident on the sample, what does P represent?
A. Radiant power transmitted by the sample
B. Radiant power absorbed by the sample
C. Sum of powers absorbed and scattered
D. Sum of powers transmitted and reflected
Answer: A
Explanation: P represents radiant power transmitted by the sample. Transmittance is the ratio of radiant power transmitted by the sample to the radiant power that is incident on it.
147. What is the unit of absorbance which can be derived from Beer Lambert’s law?
A. L mol-1 cm-1
B. L gm-1 cm-1
C. Cm
D. No unit
Answer: D
Explanation: Absorbance has no unit. The units of absorptivity, distance and concentration cancel each other. Hence, absorption has no unit.
148. What is the unit of molar absorptivity or absorptivity which is used to determine absorbance A in Beer Lambert’s formula?
A. L mol-1 cm-1
B. L gm-1 cm-1
C. Cm
D. No unit
Answer: A
Explanation: The unit of absorptivity is L mol-1 cm-1. If concentration is represented as gm per litre it becomes L gm-1 cm-1.