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Multiple choice question for engineering

Set 1

1. If a solid or liquid membrane is placed in pure water, the membrane dissolves slightly, producing an equilibrium concentration of the measured ion. This is represented as __________
a) A constant, Eo
b) Activity
c) Blank correction, Cb
d) Concentration of standard solution, Cs

View Answer

Answer: c [Reason:] If a solid or liquid membrane is placed in pure water, the membrane dissolves slightly, producing an equilibrium concentration of the measured ion. This is represented as blank correction, Cb. This is the constant background for all measurements.

2. During which of the following conditions is the blank correction not necessary?
a) If sample concentration rises in linear response region
b) If sample concentration falls in linear response region
c) If sample concentration rises in non-linear response region
d) If sample concentration falls in non-linear response region

View Answer

Answer: b [Reason:] The blank correction is not necessary if sample concentration falls in linear response region. This is the constant background for all measurements.

3. During which of the following conditions is the blank correction necessary?
a) If sample concentration rises in linear response region
b) If sample concentration falls in linear response region
c) If sample concentration rises in non-linear response region
d) If sample concentration falls in non-linear response region

View Answer

Answer: d [Reason:] The blank correction is necessary if sample concentration falls in non-linear response region. This is the constant background for all measurements.

4. Ion analysers need calibration once in which of the following durations?
a) Every two or three hours
b) Every nine or ten hours
c) Every 24 hours
d) Every 48 hours

View Answer

Answer: a [Reason:] Ion analysers need calibration every two or three hours. Temperature affects the output.

5. In ion analysers, which of the following serve the dual purpose of controlling the operating current of FET and providing current gain?
a) FET itself does it
b) SCR
c) Op-amp
d) Diode

View Answer

Answer: c [Reason:] In ion analysers, op-amp serves the dual purpose of controlling the operating current of FET and providing current gain. Two FETs are operated as source followers.

6. The presence of dirt or moisture degrades which of the following?
a) Circuit components
b) High input impedance of buffer amplifier
c) Low input impedance of buffer amplifier
d) Low output impedance of buffer amplifier

View Answer

Answer: b [Reason:] The presence of dirt or moisture degrades the high input impedance of buffer amplifier. Solder flux may also degrade it.

7. Which of the following is not a type of ground in ion analyser?
a) Chassis and electrostatic ground
b) Digital ground
c) Analog ground
d) Reference ground

View Answer

Answer: d [Reason:] There is no such point as reference ground. Three types of grounding is provided which are chassis and electrostatic ground, digital ground and analog ground.

8. The timing for microprocessor and for all signals is generated by the CPU clock.
a) True
b) False

View Answer

Answer: a [Reason:] The timing for microprocessor and for all signals is generated by the CPU clock. A crystal may be present to provide clock signals.

9. Which of the following is the only operator entry required in PC-based ion analysers?
a) Hardware set-up
b) Signal measurement
c) Calibration
d) Sample calculation

View Answer

Answer: c [Reason:] Calibration is the only operator entry required in PC-based ion analysers. The operator has to enter the concentration of calibration standards.

10. The analog and digital grounds are connected together in ion analysers.
a) True
b) False

View Answer

Answer: b [Reason:] The analog and digital grounds are not connected together in ion analysers. This is to ensure that the digital signals never flow through the same conductor as analog signals.

Set 2

1. 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

View Answer

Answer: a [Reason:] 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.

2. 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

View Answer

Answer: d [Reason:] The kinetic energy of the primary ion should be 0.3-5 keV. These primary ions are made incident on the surface.

3. 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

View Answer

Answer: c [Reason:] 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.

4. 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

View Answer

Answer: a [Reason:] Primary ion may penetrate through few layers of the surface and get embedded in the solid. This causes scattering.

5. The fragments formed during sputtering can be either neutral atoms or ions. The ions can only be positive.
a) True
b) False

View Answer

Answer: b [Reason:] The fragments formed during sputtering can be either neutral atoms or ions. The ions can be positive or negative.

6. Which of the following is the energy range of ISS?
a) 1 keV
b) 2 keV
c) 4 keV
d) 8 keV

View Answer

Answer: a [Reason:] The energy range of the ISS is 1 keV. ISS stands for ion scattering spectroscopy.

7. Which of the following is the spectral range of SIMS?
a) 0-10 amu
b) 0-100 amu
c) 0-500 amu
d) 0-1000 amu

View Answer

Answer: c [Reason:] The spectral range of SIMS is 0-500 amu. SIMS stands for secondary ion mass spectroscopy.

8. Both ISS and SIMS have depth profiling capability.
a) True
b) False

View Answer

Answer: a [Reason:] Both ISS and SIMS have depth profiling capability. ISS is slow in depth profiling but SIMS is rapid.

9. Which of the following is denotes the absolute quantitative analysis of SIMS?
a) 30%
b) 70%
c) 50%
d) Not possible

View Answer

Answer: d [Reason:] Absolute quantitative analysis is not possible in SIMS. It is possible in ISS.

10. Which of the following is the amount of matrix effect that occurs in SIMS?
a) Very low
b) Low
c) Some
d) Severe

View Answer

Answer: d [Reason:] Severe matrix effects occur in SIMS. Some matrix effects occur in ISS.

11. Which of the following is the x-y resolution of ISS?
a) 1 µ
b) 10 µ
c) 100 µ
d) 1000 µ

View Answer

Answer: c [Reason:] The x-y resolution of ISS is 100 µ. It has poor x-y resolution.

12. Which of the following is the x-y resolution of SIMS?
a) 1 µ
b) 10 µ
c) 100 µ
d) 1000 µ

View Answer

Answer: a [Reason:] The x-y resolution of SIMS is 1 µ. It has this resolution when used with ion microprobe.

Set 3

1. Which of the following is not an ion transducer or detector?
a) Faraday cup collector
b) Channeltron
c) Micro-channel plate
d) Flame ionization detector

View Answer

Answer: d [Reason:] Flame ionization detector is not an ion transducer. It is a detector used in chromatography.

2. Which of the following is similar to photo multiplier transducer?
a) Faraday cup collector
b) Channeltron
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: d [Reason:] Electron multiplier transducer is similar to photo multiplier transducer. The difference is that its primary cathode detects ions rather than photons.

3. Which of the following is used in places where ion currents are very low?
a) Faraday cup collector
b) Channeltron
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: d [Reason:] Electron multiplier transducer is used in places where ion currents are very low. Its primary cathode detects ions.

4. Discrete type electron multiplier transducers can provide current gain upto which of the following?
a) 102
b) 105
c) 107
d) 1011

View Answer

Answer: c [Reason:] Discrete type electron multiplier transducers can provide current gain upto 102. Upto 20 dynodes need to be used for this purpose.

5. Continuous dynode electron multiplier transducer is a trumpet shaped device made with which of the following?
a) Glass doped with lead
b) Steel doped with bronze
c) Phosphor bronze doped with iron
d) Iron doped with calcium

View Answer

Answer: a [Reason:] Continuous dynode electron multiplier transducer is a trumpet shaped device made of glass. It is heavily doped with lead.

6. The potential maintained across the continuous dynode multiplier transducer is which of the following?
a) 1 to 5kV
b) 5 to 10kV
c) 2.5 to 6.2kV
d) 1.8 to 2kV

View Answer

Answer: d [Reason:] The potential maintained across the continuous dynode multiplier transducer is 1.8 to 2kV. Electrons cascade down the tube.

7. Which of the following are not the characteristics of electron multiplier transducer?
a) Rugged
b) Reliable
c) Microsecond of response time required
d) High current gain

View Answer

Answer: c [Reason:] Electron multiplier transducer requires only nanosecond of response time. It provides high current gain.

8. Which of the following are true about dynodes used in discrete dynode electron multiplier?
a) The dynodes are all kept at same voltage
b) Successive dynodes are held at lower potential
c) Successive dynodes are held at higher potential
d) All dynodes are held at very low potential

View Answer

Answer: c [Reason:] In discrete dynode electron multiplier, successive dynodes are held at higher potential. Dynodes are metal plates with copper or beryllium surfaces.

9. In which of the following detectors, the collector is placed in an inclined manner?
a) Faraday cup collector
b) Channeltron
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: a [Reason:] The collector is placed in an inclined manner in faraday cup collector. This is to reflect the ions away from the entrance of the cup.

10. Which of the following is the least sensitive ion detector?
a) Faraday cup collector
b) Channeltron
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: a [Reason:] Faraday cup collector is the least sensitive ion detector. It is used in places where great sensitivity is not required.

11. Photographic plates are coated with which of the following?
a) Lead
b) Quartz
c) Silver bromide
d) Mercuric sulphate

View Answer

Answer: c [Reason:] Photographic plates are coated with silver bromide. These are sensitive to energetic ions.

12. Which of the following detectors are well suited for spark source instruments?
a) Faraday cup collector
b) Photographic plates
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: b [Reason:] Photographic plates are well suited for spark source instruments. It has great sensitivity.

13. Photographic plates have greater sensitivity and resolution than electron multipliers.
a) True
b) False

View Answer

Answer: a [Reason:] Photographic plates have greater sensitivity and resolution than electron multipliers. This is because they integrate the ion signals over a period of time.

14. Which of the following detectors consist of an array of glass capillaries?
a) Faraday cup collector
b) Photographic plates
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: c [Reason:] Micro-channel plate consists of an array of glass capillaries. They are coated with electron emissive materials.

15. Which of the following detectors can be used for ions with short life time?
a) Faraday cup collector
b) Photographic plates
c) Micro-channel plate
d) Electron multiplier transducer

View Answer

Answer: b [Reason:] Photographic plates can be used for ions with short life time. This is because they integrate the ion signal over a period of time.

Set 4

1. Introduction of total HPLC effluent into MS is feasible.
a) True
b) False

View Answer

Answer: b [Reason:] Introduction of total HPLC effluent into MS is not feasible. The simplest method is the introduction of liquid from LC to the MS ion source region.

2. 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

View Answer

Answer: c [Reason:] The gas burden from conventional LC flow rates creates nearly 20 times more gas than cryo-pumped vacuum system can handle.

3. Which of the following should be in position to split the effluent?
a) Interface
b) Ion source
c) Makeup gas
d) Microbore

View Answer

Answer: a [Reason:] Interface should be in position to split the effluent. LC-MS is a very advantageous method.

4. Which of the following is the most commonly used interface?
a) Nebulizer
b) Chopper
c) Filter
d) Vapourising chamber

View Answer

Answer: a [Reason:] Nebulizer is the most commonly used interface. The nebulizer gas and the make-up gas are introduced coaxially into the heated nebulization region.

5. 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
b) 1-15

View Answer

Answer: b [Reason:] 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.

6. 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

View Answer

Answer: c [Reason:] 125-150oC is the normal nebuliser temperature used in LC mass spectrometry. It is suitable for a variety of applications.

7. 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

View Answer

Answer: d [Reason:] The ions are focussed and de-clustered through a dry nitrogen region. It is then sent into the high vacuum analyser.

8. The ions are passed into the high vacuum analyser through which of the following?
a) Orifice
b) Nozzle
c) Nebulizer
d) Venturi tube

View Answer

Answer: a [Reason:] The ions are sent into the high vacuum analyser through an orifice. It is then mass analysed.

9. Using an interface would reduce detection limit and sensitivity.
a) True
b) False

View Answer

Answer: a [Reason:] The total effluent must be split. Using an interface would reduce detection limit and sensitivity.

10. 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

View Answer

Answer: a [Reason:] 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.

Set 5

1. In liquid scintillation counter, which of the following is a fluorescent substance?
a) Solvent
b) Solute
c) Crystal
d) Reagent

View Answer

Answer: b [Reason:] In liquid scintillation counter, a mixture of solvent and solute is used. The solute is a fluorescent substance.

2. When UV light is absorbed by the fluor molecules the light emitted is in which of the following colours?
a) Pink
b) Red
c) Green
d) Blue

View Answer

Answer: d [Reason:] When UV light is absorbed by the fluor molecules the light emitted is in blue colour. Light is emitted when the molecules return to the ground state.

3. In liquid scintillation counter, which of the following is used to convert light into electrical signals?
a) Photo multiplier tube
b) Photo emissive tube
c) Photo voltaic cell
d) Photo reflector

View Answer

Answer: a [Reason:] The photo multiplier tube converts light into electrical signals in liquid scintillation counter. Two photo multiplier tubes are used in liquid scintillation counter.

4. The reduction in counting efficiency of the scintillation detector is called as __________
a) Disintegration
b) Decay
c) Quenching
d) Reduction

View Answer

Answer: c [Reason:] The reduction in counting efficiency of the scintillation detector is called as quenching. Substances added to the counting vial can reduce the efficiency.

5. Which of the following is not a type of quenching?
a) Chemical quench
b) Interference quench
c) Colour quenching
d) Self-absorption

View Answer

Answer: b [Reason:] There are three types of quenching. Interference quench is not a type of quenching.

6. In which type of quenching, the radiation emitted by the isotope is not detected due to absorption of the radiation by the sample itself?
a) Chemical quench
b) Interference quench
c) Colour quenching
d) Self-absorption

View Answer

Answer: d [Reason:] In self-absorption, the radiation emitted by the isotope is not detected due to absorption of the radiation by the sample itself. It may occur due to precipitates.

7. Variation of gain with temperature does not cause instability.
a) True
b) False

View Answer

Answer: b [Reason:] Variation of gain with temperature causes instability. There are various other factors that cause instability.

8. Due to the presence of red, green and yellow colour in the vial, which of the following occurs?
a) Chemical quench
b) Interference quench
c) Colour quenching
d) Self-absorption

View Answer

Answer: c [Reason:] Scintillators emit light in the blue region of the spectrum. Due to the presence of other colours, colour quenching may occur.

9. A quench curve can be constructed by plotting the counting efficiency versus ____________
a) Q-number
b) Quench factor
c) H-number
d) Disintegrations

View Answer

Answer: c [Reason:] A quench curve can be constructed by plotting the counting efficiency versus H-number. This is done using a set of samples with known activity.

10. Photomultipliers used in Liquid scintillation detectors are a source of instability.
a) True
b) False

View Answer

Answer: a [Reason:] Photomultipliers used in Liquid scintillation detectors are a source of instability. Various factors cause instability.