QUES: So an additional problem beyond canceling the unwanted reactance is of matching the remaining resistive impedance to the characteristic impedance of the transmission line. In principle this can always be done with a transformer, however the turns ratio of a transformer is not adjustable. A general matching network with at least two adjustments can be made to correct both components of impedance. Matching networks using discrete inductors and capacitors will have losses associated with those components, and will have power restrictions when used for transmitting. Avoiding these difficulties, commercial antennas are generally designed with fixed matching elements or feeding strategies to get an approximate match to standard coax, such as 50 or 75 Ohms. Antennas based on the dipole (rather than vertical antennas) should include a balun in between the transmission line and antenna element, which may be integrated into any such matching network.

How many ohms are in are in a standard coax?
What is the answer?
ANS: 50 or 75
QUES: In the 21st century the most famous department store in Russia is GUM in Moscow, followed by TsUM and the Petrovsky Passage. Other popular stores are Mega (shopping malls), Stockmann, and Marks & Spencer. Media Markt, M-video, Technosila, and White Wind (Beliy Veter) sell large number of electronic devices. In St. Petersburg The Passage has been popular since the 1840s. 1956 Soviet film Behind Store Window ( ) on YouTube depicts operation of a Moscow department store in 1950's.

Where is the most notable Russian department store not located?
What is the answer?
ANS: unanswerable
QUES: A sequence of events, or series of events, is a sequence of items, facts, events, actions, changes, or procedural steps, arranged in time order (chronological order), often with causality relationships among the items. Because of causality, cause precedes effect, or cause and effect may appear together in a single item, but effect never precedes cause. A sequence of events can be presented in text, tables, charts, or timelines. The description of the items or events may include a timestamp. A sequence of events that includes the time along with place or location information to describe a sequential path may be referred to as a world line.

What may the description of events include?
What is the answer?
ANS:
a timestamp