This set of Video Engineering Multiple Choice Questions & Answers focuses on “Television Fundamentals – Solid State Picture Transducers”.
1. Which type of transducers scientist discovered after the conventional picture tubes?
a) Solid state
b) Liquid state
c) Gaseous state
d) Plasma state
Explanation: The conventional picture tubes are made of thermionic tubes that emit electrons in vacuum using heated cathode filament. But there are certain disadvantages associated to this type of picture tubes such as requirement of high voltage, vacuum, heater and its bulky size. So the scientists discovered solid-state transducers and developed the flat panel. Ultimately, they invented devices like LED, gas discharge plasma and LCD.
2. Which screens are made up of liquid crystal sandwiched between two glass plates?
Explanation: LCD screens are made up of liquid crystals which are sandwiched between two glass plates. Pictures are created by varying the amount of electrical charge applied to liquid crystals. LCD technology is based on manipulation of polarized light. Two thin polarizing sheets are laminated to two glass substrates containing a thin layer of liquid crystal.
3. Most LCD display use passive matrix technology.
Explanation: The above statement is false. Most LCD displays use active matrix technology. A thin film transistor (TFT) arranges tiny transistors and capacitors in a matrix on the glass of the display. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column.
4. In which monitor would the image look dimmer or even disappear when viewed from an angle?
Explanation: When an LCD monitor is viewed from an angle the image can look dimmer or even disappear. Colors can also be misrepresented. To compensate for this problem, LCD monitor makers have designed wider viewing angles. Manufacturers give a measure of viewing angle in degrees. Greater values of degrees make better viewing. In general, acceptable values are between 120 and 170 degrees.
5. One nit is not equal to one candela.
Explanation: The above statement is false. The amount of light an LCD monitor produces is measured in Luminance or brightness. One nit equals one cd / m2. It is given in nits or candela per square meter (cd / m2). Typical brightness ratings for monitors that perform general-purpose tasks range from 250 to 350 cd / m2.
6. What is the range of the usual contrast ratio of LCD TV?
a) 600:1 to 1000:1
b) 500:1 to 700:1
c) 200:1 to 10000:1
d) 300:1 to 900:1
Explanation: The contrast ratio provides the degree of difference of an LCD monitors ability to produce bright whites and the dark blacks. The figure is a ratio. Usually, contrast ratios range from 600:1 to 1000:1, and they can be rated even much higher.
7. Which monitor can rotate from landscape to portrait mode?
Explanation: LCD monitors, unlike CRT monitors, have more flexibility for positioning the screen as required. They can swivel, tilt up and down, and even rotate from landscape to portrait mode. Because they are light in weight and thin, most LCD monitors have built-in brackets for wall or arm mounting.
8. What do LEDs consist of which glow when exposed to electric current?
a) Small semiconductors
b) Liquid semiconductors
c) Big and Small semiconductors
d) Big semiconductors
Explanation: An LED TV illuminates its LCD panel with LEDs. LED consists of small semiconductors, which glow during exposure to electric current. LED TVs are thin, light and energy efficient. The picture quality and contrast ratio is also excellent in LED TVs.
9. Which type of TV does not work properly at high altitude?
Explanation: Plasma TV provides more clarity of picture even when viewed on the side or at an angle. It has a slow response time and consumes more power. Due to pressure problem at high altitude, Plasma TV does not work properly.
10. Which chemical coating is converted into red, green and blue colors when it comes in contact with UV rays in plasma screens?
a) Hydrochloric acid
Explanation: Plasma screen uses a matrix of small gas plasma cells which is coated inside with Phosphor chemicals. When voltage is applied, plasma state releases UV rays. This invisible UV light converts phosphor coating into red, green and blue colors and thus displays images.
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.