151. In the United States the television broadcast standard is…?
(a) PAL (b) NTSC (c) SECAM (d) RGB
Answer
Answer : (b)
Explanation
Explanation : PAL and SECAM are standards used in other countries. RGB stands for red, green, and blue – the colors of light used to create an image in a color tv set and is often used as a format name for computer monitors. Let us discuss.
152. Voltage is sometimes referred to as EMF, or Electromotive…?
(a) Field (b) Factor (c) Flash (d) Force
Answer
Answer : (d)
Explanation
Explanation : The term EMF, or Electromotive Force, its use now in decline, is attributed to Italian physicist Alessandro Volta (1745-1827). Today we generally use the term “voltage” – can you guess why we call it that? Let us discuss.
153. When measuring the characteristics of a small-signal amplifier, say for a radio receiver, one might be concerned with its “Noise…”?
(a) Fundamental (b) Fall (c) Force (d) Figure
Answer
Answer : (d)
Explanation
Explanation : “Noise figure” is one critical parameter for determining the “quality” of a low-noise, small-signal, amplifier, and perhaps more importantly, the sensitivity of the overall receiver system. It is especially important for VHF (very high frequency) – and higher frequency – designs where most of the undesired “noise” (noise that masks or overpowers the desired signals) is generated internal to the electronics itself. In HF (high frequency) applications, atmospheric noise plays a much larger role in determining overall useful sensitivity, so a circuit’s “noise figure” is less important. Let us discuss.
154. A given signal’s second harmonic is twice the given signal’s __________ frequency…?
(a) Fourier (b) Foundation (c) Fundamental (d) Field
Answer
Answer : (c)
Explanation
Explanation : A given signal’s second harmonic is twice the given signal’s fundamental frequency. Harmonics are generated when there are non-linearities in an amplifier (there are always non-linearities). The worse the non-linearities, the more harmonics. A signal at 27.5 MHz (approximate frequency for US citizen’s band) would have a second harmonic at 55.0 MHz (on US channel 2!). Can you see why there might be problems? A CB operator might do well to place a low-pass filter on his radio. Let us discuss.
155. “FET” is a type of transistor, Its full name is ________ Effect Transistor…?
(a) Field (b) Factor (c) Flash (d) Force
Answer
Answer : (a)
Explanation
Explanation : The terminals of FETs are called gate, drain and source. You might be more familiar with bipolar junction transistors (BJTs), which have terminals called base, collector and emitter. FETs were conceptualized first, but BJTs were easier to produce and so developed sooner. Let us discuss.
5555555555156. The most common format for a home video recorder is VHS. VHS stands for...? (a) Video Home System (b) Very high speed (c) Video horizontal standard (d) Voltage house standard
Tags: video, vhs, standard, science, technology, format, stands, system, speed, voltage
5555555555162. Changing computer language of 1's and 0's to characters that a person can understand is... (a) Highlight (b) Clip art (c) Decode (d) Execute
5555555555186. The "http" you type at the beginning of any site's address stands for... (a) HTML Transfer Technology Process (b) Hyperspace Terms and Tech Protocol (c) Hyperspace Techniques & Tech Progress (d) Hyper Text Transfer Protocol
5555555555132. Hardware devices that are not part of the main computer system and are often added later to the system. (a) Peripheral (b) Clip art (c) Highlight (d) Execute
5555555555156. The most common format for a home video recorder is VHS. VHS stands for...? (a) Video Home System (b) Very high speed (c) Video horizontal standard (d) Voltage house standard