Instrumentation Transducers

Photo Electric Transducers

Question 1
Marks : +2 | -2
Pass Ratio : 43%
Photoelectric devices are sensitive to all wavelength.
True
False
Explanation:
Photoelectric devices are sensitive to certain wavelength only hence they should be calibrated before every use.
Question 2
Marks : +2 | -2
Pass Ratio : 14%
In photo emissive transducers, electrons are attracted by ___________
Cathode
Anode
Grid
Body
Explanation:
In photo emissive transducers, electrons emitted by the cathode are attracted by anode plates.
Question 3
Marks : +2 | -2
Pass Ratio : 29%
Semiconductor layer using silicon and germanium is known as _______________
Photo diodes
Photo junction diodes
Photo material
Photo sensitive materials
Explanation:
Photo junction diodes are semiconductor layers formed by silicon and germanium which are used in photovoltaic cells.
Question 4
Marks : +2 | -2
Pass Ratio : 14%
Which of the following are used to form photo transistors?
Two photo diodes
Three photo diodes
Normal diodes
None of the mentioned
Explanation:
Photo transistors are formed by placing two photo diodes back to back.
Question 5
Marks : +2 | -2
Pass Ratio : 14%
Which of the following materials can be used as photoconductive transducer?
Selenium
Silicon
Germanium
All of the mentioned
Explanation:
Photoconductive cells are materials which changes conductivity on the application of light.
Question 6
Marks : +2 | -2
Pass Ratio : 29%
Photo resistive cells are _____________
Active device
Passive device
Insulating device
None of the mentioned
Explanation:
Passive devices are those doesn’t require an external power source. Resistors and LDR’s are passive devices.
Question 7
Marks : +2 | -2
Pass Ratio : 14%
Photo transistor is a three terminal device.
True
False
Explanation:
Photo transistor contains only two terminals, which are collector and emitter. Base region is illuminated.
Question 8
Marks : +2 | -2
Pass Ratio : 29%
LDR’s are also called _______________
Photo voltaic cell
Photo resistive cell
Photo emissive cell
All of the mentioned
Explanation:
Photo resistive cells and LDR works on the interaction of light and its effect on resistance change.
Question 9
Marks : +2 | -2
Pass Ratio : 43%
Why inert gas is used in photo electric transducers?
To increase efficiency
To increase sensitivity
To increase robustness
None of the mentioned
Explanation:
Inert gas of pressure 1mm Hg is filled in a tube of photoelectric transducer to increase sensitivity.
Question 10
Marks : +2 | -2
Pass Ratio : 29%
Which of the following quantities are insensitive to solid state semiconductor photoelectric transducers?
X ray
Gamma ray
Alpha and beta rays
None of the mentioned
Explanation:
Solid state photoelectric transducer made up of semiconductor are insensitive to X rays, gamma rays, alpha and beta rays etc.