This set of Aircraft Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Light-Emitting Displays”.
1. To display Numeric Data by means of Emission of Light, we use _____
a) Liquid Crystal Display
b) Counters
c) Quantitative Display
d) Qualitative Display
View Answer
Explanation: Liquid Crystal Display is used in data representation from Light Emission, in which each bar is electrically separate and driven by selected Logic Circuit which helps to emit light in the form of indicated number.
2. In LCD, which type of thin and transparent Conductor is used?
a) Titanium Oxide
b) Indium-Tin Oxide
c) Aluminium Oxide
d) Stainless Steel
View Answer
Explanation: Indium Tin Oxide is mainly used in LCD because it is electrically conductive, optically transparent and it can be easily deposited as it is thin, whereas Stainless Steel is very less Conductive. Titanium and Aluminium Oxides are not thin and it is difficult to deposit them on LCD screen.
3. In LCD, the space between two plates is filled with ______
a) Alkaline Material
b) Acidic Material
c) Non-Conducting Material
d) Nematic Material
View Answer
Explanation: Space between two plates is filled with Nematic material, because it is a liquid Crystal material, it has a thread like structure, which orientates in particular direction and this whole assembly works as a Parallel Plate Capacitor (Nematic material between two plates).
4. Low Voltage Current is applied between two plates of LCD to make it reflective.
a) True
b) False
View Answer
Explanation: When low voltage current is applied between two plates of LCD, the thread like Nematic Material between these plates changes its orientation or its orientation is disturbed which results in changing its optical behaviour from transparent to reflective.
5. The optical change occurring in Nematic Material from transparent to reflective is known as _____
a) Gamma Ratio
b) Reflection Ratio
c) Transparency Ratio
d) Contrast Ratio
View Answer
Explanation: Contrast ratio is the ratio of “reflection or transmission of light through a segmented area” to “reflection of the light from the background”. Hence, the optical change happening in Nematic material from transparent to reflective can be termed as Contrast ratio.
6. Which of the following LCD type works on the principle of Forward Light Scattering?
a) Fringe Field
b) Field Effect
c) Dynamic-Scattering
d) Twisted Nematic
View Answer
Explanation: Dynamic Scattering LCDs work on the principle of forward light scattering, in which the scattering of light occurs due to turbulence of the ions of Liquid Crystal Material because of the current applied at segment electrodes.
7. For Transmissive Read-Out, Back-Light Source is provided.
a) True
b) False
View Answer
Explanation: In case of Transmissive Read-Out we have to provide Back-Light Source in which light is directed by Light-Control Film which helps in scattering the light towards Observer to produce digit or character on the dark background.
8. The Field Effect LCD implements additional plates known as _____
a) Polarizers
b) Depolarizers
c) Saturators
d) Reflectors
View Answer
Explanation: Field Effect LCD implements additional plates which are known as Polarizers. This configuration causes the plane of polarization to be reflected by 90 degrees as it passes the LCD and according to the nature of light, it helps LCD to be transmissive or opaque.
9. In LED, what is molded on the plastic covering, which surrounds the chip?
a) Magnesium Phosphide
b) Indium-Tin Oxide
c) Stainless Steel
d) Gallium Arsenide Phosphide
View Answer
Explanation: Gallium Arsenide Phosphide (GaAsP) is molded into a transparent plastic covering which not only serves to protect the chip, but also as a diffuser lens in Light Emitting Diode. We can also vary the proportion of Gallium Arsenide Phosphide to get different colours of LED.
10. Following Diagram indicates _____
a) LCD (Liquid Crystal Display)
b) LED (Light Emitting Diode)
c) Circular Display
d) Synchroscope
View Answer
Explanation: Above diagram indicates Seven Segment Display which is a type of LCD. This digital display indicates numbers from 0 to 9 using seven segments of displays which have respective Logic Circuit to trigger specific segments for representation of corresponding number.
11. The following Diagram represents _____
a) Liquid Crystal Display
b) Light Emitting Diode
c) Speedometer
d) Gyro-Horizon
View Answer
Explanation: Above Diagram indicates Light Emitting Diode as it has two terminals which acts as anode and cathode. When current passes through these terminals, then at the top where both terminals are joined by small wire, Light is emitted from this wire because of the Continuous flow of electrons which produces Heat and Light energy.
Sanfoundry Global Education & Learning Series – Aircraft Instrumentation.
To practice all areas of Aircraft Instrumentation, here is complete set of Multiple Choice Questions and Answers.
