Analytical Instrumentation Questions and Answers – Method Based on Ionization of Gases

This set of Analytical Instrumentation Questions and Answers for Experienced people focuses on “Method Based on Ionization of Gases”.

1. Gases emit radiation under which of the following conditions which can be used for determination of gases?
a) When mixed with other gases
b) When kept at suitable temperature
c) With sufficient electrical excitation and at suitable pressures
d) When exposed to radiation
View Answer

Answer: c
Explanation: Gases emit radiation with sufficient electrical excitation and at suitable pressures. Gases emit radiation in different ways. It can be in the form of spark, arc or glow discharge in different parts of the radiation spectrum.

2. Which of the following measuring technique is utilized for measuring nitrogen?
a) By using a method based on gas density
b) By using paramagnetic analyzers
c) By using magnetic wind instruments
d) By using a photospectrometer where a gas sample is analysed and detected with a photocell
View Answer

Answer: d
Explanation: By using a photospectrometer gas sample is analysed, for measuring nitrogen. It is then selectively filtered by using a photocell which provides an appropriate electric signal.

3. The characteristic emission of which colour, when discharge takes place in a low pressure chamber containing gas sample, will indicate the presence of nitrogen while using photospectrometer?
a) Purple
b) Blue
c) Pink
d) Green
View Answer

Answer: a
Explanation: The characteristic emission of purple colour, when discharge takes place in a low pressure chamber containing gas sample, will indicate the presence of nitrogen while using photospectrometer. These are usually employed in medical applications.
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4. Sample rates of nitrogen meter can be adjusted by doing which of the following?
a) By modifying the amplifier
b) With the help of the needle valve
c) By modifying the detector
d) By changing chopper frequency
View Answer

Answer: b
Explanation: Sample rates of nitrogen meter can be adjusted with the help of a needle valve. Modern nitrogen analyzers have digital displays.

5. Which of the following is the normal sampling rate used in nitrogen meters?
a) 13 ml/min
b) 33 ml/min
c) 3 ml/min
d) 43 ml/min
View Answer

Answer: c
Explanation: The normal sampling rate used in nitrogen meters is 3 ml/min. Modern nitrogen analyzers have digital displays.
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6. Nitrogen meters are calibrated for which of the following to measure nitrogen?
a) Mixture of nitrogen and air
b) Water saturated mixture of nitrogen and oxygen
c) Mixture of nitrogen and hydrogen
d) Nitrogen
View Answer

Answer: b
Explanation: Nitrogen meters are calibrated for water saturated mixture of nitrogen and oxygen. Hence, this calibration cannot be used for dry gases.

7. Why is nitrogen meters generally not calibrated for dry gases while measuring nitrogen?
a) It causes error
b) Range decreases
c) Reading tend to be non-linear
d) It cannot be measured
View Answer

Answer: a
Explanation: Nitrogen meters are generally not calibrated for dry gases because it will lead to error in the reading. The error will be up to 2%.
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8. In which of the following ways can nitrogen be calibrated for dry gases?
a) By modifying the amplifier
b) By adjusting the needle valve
c) By modifying the detector
d) By changing chopper frequency
View Answer

Answer: b
Explanation: Nitrogen can be calibrated for dry gases by adjusting the needle valve. In this way, the error will be compensated.

9. The voltage required for striking the discharge in the presence of nitrogen is 1500V.
a) True
b) False
View Answer

Answer: a
Explanation: The voltage required for striking the discharge in the presence of nitrogen is 1500V. This voltage is generated using a DC-DC converter.
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10. The light output from the discharge tube is interrupted by means of a rotating slotted disc.
a) True
b) False
View Answer

Answer: a
Explanation: The light output from the discharge tube is interrupted by means of a rotating slotted disc. Hence, a chopped output is obtained.

Sanfoundry Global Education & Learning Series – Analytical Instrumentation.

To practice all areas of Analytical Instrumentation for Experienced people, 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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