Analytical Instrumentation Questions and Answers – Liquid Scintillation Counters

This set of Analytical Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Detection System of Liquid Chromatography”.

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
Explanation: 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
Explanation: 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
Explanation: The photo multiplier tube converts light into electrical signals in a liquid scintillation counter. Two photo multiplier tubes are used in the liquid scintillation counter.
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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
Explanation: The reduction in counting efficiency of the scintillation detector is called as quenching. Substances added to the counting vial can reduce 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
Explanation: 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
Explanation: In self-absorption, the radiation emitted by the isotope is not detected due to the 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
Explanation: Variation of gain with temperature causes instability. There are various other factors that cause instability.
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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
Explanation: 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
Explanation: 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.
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10. Photomultipliers used in Liquid scintillation detectors are a source of instability.
a) True
b) False
View Answer

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

Sanfoundry Global Education & Learning Series – Analytical Instrumentation.

To practice all areas of Analytical Instrumentation, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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