Instrumentation Transducers Questions and Answers – Photo Electric Transducers

This set of Instrumentation Transducers Multiple Choice Questions & Answers (MCQs) focuses on “Photo Electric Transducers”.

1. Photoelectric devices are sensitive to all wavelength.
a) True
b) False
View Answer

Answer: b
Explanation: Photoelectric devices are sensitive to certain wavelength only hence they should be calibrated before every use.

2. In photo emissive transducers, electrons are attracted by ___________
a) Cathode
b) Anode
c) Grid
d) Body
View Answer

Answer: b
Explanation: In photo emissive transducers, electrons emitted by the cathode are attracted by anode plates.

3. Why inert gas is used in photo electric transducers?
a) To increase efficiency
b) To increase sensitivity
c) To increase robustness
d) None of the mentioned
View Answer

Answer: b
Explanation: Inert gas of pressure 1mm Hg is filled in a tube of photoelectric transducer to increase sensitivity.
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4. Which of the following quantities are insensitive to solid state semiconductor photoelectric transducers?
a) X ray
b) Gamma ray
c) Alpha and beta rays
d) None of the mentioned
View Answer

Answer: d
Explanation: Solid state photoelectric transducer made up of semiconductor are insensitive to X rays, gamma rays, alpha and beta rays etc.

5. LDR’s are also called _______________
a) Photo voltaic cell
b) Photo resistive cell
c) Photo emissive cell
d) All of the mentioned
View Answer

Answer: b
Explanation: Photo resistive cells and LDR works on the interaction of light and its effect on resistance change.
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6. Photo resistive cells are _____________
a) Active device
b) Passive device
c) Insulating device
d) None of the mentioned
View Answer

Answer: b
Explanation: Passive devices are those doesn’t require an external power source. Resistors and LDR’s are passive devices.

7. Which of the following materials can be used as photoconductive transducer?
a) Selenium
b) Silicon
c) Germanium
d) All of the mentioned
View Answer

Answer: d
Explanation: Photoconductive cells are materials which changes conductivity on the application of light.
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8. Semiconductor layer using silicon and germanium is known as _______________
a) Photo diodes
b) Photo junction diodes
c) Photo material
d) Photo sensitive materials
View Answer

Answer: b
Explanation: Photo junction diodes are semiconductor layers formed by silicon and germanium which are used in photovoltaic cells.

9. Which of the following are used to form photo transistors?
a) Two photo diodes
b) Three photo diodes
c) Normal diodes
d) None of the mentioned
View Answer

Answer: a
Explanation: Photo transistors are formed by placing two photo diodes back to back.
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10. Photo transistor is a three terminal device.
a) True
b) False
View Answer

Answer: b
Explanation: Photo transistor contains only two terminals, which are collector and emitter. Base region is illuminated.

Sanfoundry Global Education & Learning Series – Instrumentation Transducers.

To practice all areas of Instrumentation Transducers, 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 - Founder & CTO at Sanfoundry
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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