This set of Video Engineering Multiple Choice Questions & Answers (MCQs) focuses on “LCD Technology”.
1. Which of the following scientist discovered liquid crystal?
a) Friedrich Reinitzer
b) Ada Lovelace
c) George Ohm
d) Joseph Henry
View Answer
Explanation: Till the late 19th century, scientists thought that there are three States of matter- solid, liquid and gas. But, in 1888 an Austrian chemist named Friedrich Reinitzer (1857-1927) discovered liquid crystals. Liquid crystal state lies between solid and liquid States. It has some of the components of solid and some of the fluidity of liquid.
2. In which phase the molecules have definite order of patterns in LCD technology?
a) Negative
b) Positive
c) Nematic
d) Smectic
View Answer
Explanation: Liquid crystal has two phases which are Nematic and Smectic. In Nematic phase, molecules have definite order of pattern. They change their pattern on application of magnetic or electric charge across them and these forms the basis of LCD displays. Nematics are liquid in nature.
3. Each pixel in the LCD has a polarized glass filter in front of it and behind it at 90 degrees.
a) True
b) False
View Answer
Explanation: There’s a large bright light at the back of the LCD screen that shines out toward the viewer. In front of this, there are millions of pixels; each pixel is made up of smaller areas called sub pixels that are colored red, blue or green. Each pixel has a polarized glass filter in front of it and behind it at 90 degrees. Between the two polarizing filters there’s a nematicliquid crystal that can be switched ON or OFF electronically.
4. Which matrix uses the substrate which is made up of transparent conductive material called Indium Tin Oxide in LCD technology?
a) Active
b) Passive
c) Positive
d) Negative
View Answer
Explanation: Passive Matrix LCDs use a simple framework to supply the charge to a particular pixel on the display. The process of creating a Framework is very complex. It starts with two glass layers called substrates and they are usually made up of transparent conductive material called Indium Tin Oxide. One substrate is for rows and other for columns.
5. Displays having an active matrix structure are employing super twisted nematic (STN) or dual scan twisted nematic (DSTN) in LCD technology.
a) True
b) False
View Answer
Explanation: Passive Matrix LCDs are used for applications less demanding than laptop and TVs like calculator, digital watches etc. Displays having a passive matrix structure are employing super twisted nematic (STN) or dual scan twisted nematic (DSTN). Passive Matrix system has certain drawbacks like the slow time response and non-precise voltage control.
6. Which of the following matrix is used in LCD computer monitors and televisions?
a) Active
b) Passive
c) Negative
d) Positive
View Answer
Explanation: To overcome the disadvantages of passive matrix, active matrix display uses a thin film transistor (TFT) for delivery of charge. TFTs are tiny switching transistors and capacitors. They are arranged in a matrix on a glass substrate. High resolution color displays such as modern LCD computer monitors and televisions use an active Matrix structure.
7. How many levels of brightness per pixel is mostly displayed in LCD?
a) 164
b) 32
c) 256
d) 280
View Answer
Explanation: In LCD, most displays create 256 levels of brightness per pixel. Red, Blue and Green, three sub pixels should be present in an LCD that can show colors in order to create one color pixel. A range of 256 color shades are enough to display full spectrum of visible light, that can be obtained by controlling intensity of applied voltage to each Sub pixels.
8. Which of the following TV was made up of data display screens?
a) LED
b) LCD
c) OLED
d) Plasma
View Answer
Explanation: LCD screen enable good reproduction with high resolution and high contrast. It can be built in much larger size as compared to the CRT tubes. Earlier, LCD displays where made up of data display screens where there was less moment and slow refresh rate. With improvement in LCD Technology, LCD panels are used as TV receiver screens where object often moves faster.
Sanfoundry Global Education & Learning Series – Video Engineering.
To practice all areas of Video Engineering, 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]
