Article: This is a consequence of Lorentz reciprocity. For an antenna element  not connected to anything (open circuited) one can write . But for an element  which is short circuited, a current is generated across that short but no voltage is allowed, so the corresponding . This is the case, for instance, with the so-called parasitic elements of a Yagi-Uda antenna where the solid rod can be viewed as a dipole antenna shorted across its feedpoint. Parasitic elements are unpowered elements that absorb and reradiate RF energy according to the induced current calculated using such a system of equations.

Question: When is the element not allowed voltage?
Ans: short circuited


Article: Nevertheless, the ethno-geographic caste hierarchy favoring the Mongols and other ethnicities were accorded higher status than the Han Chinese majority. Although Han Chinese who were recruited as advisers were often actually more influential than high officials, their status was not as well defined. Kublai also abolished the imperial examinations of China's civil service legacy, which was not reinstated until Ayurbarwada Buyantu Khan's reign (1311–1320). Rossabi writes that Kublai recognized that in order to rule China, "he had to employ Chinese advisors and officials, yet he could not rely totally on Chinese advisers because he had to maintain a delicate balancing act between ruling the sedentary civilization of China and preserving the cultural identity and values of the Mongols." And "in governing China, he was concerned with the interests of his Chinese subjects, but also with exploiting the resources of the empire for his own aggrandizement. His motivations and objectives alternated from one to the other throughout his reign," according to Rossabi. Van Praag writes in The Status of Tibet that the Tibetans and Mongols, on the other hand, upheld a dual system of rule and an interdependent relationship that legitimated the succession of Mongol khans as universal Buddhist rulers, or chakravartin. Van Praag writes that "Tibet remained a unique part of the Empire and was never fully integrated into it," citing examples such as a licensed border market that existed between China and Tibet during the Yuan.

Question: During the Yuan what existed between China and Tibet? 
Ans: a licensed border market


Article: Goetz set out an ambitious schedule. Universal-International became responsible for the American distribution of Rank's British productions, including such classics as David Lean's Great Expectations (1946) and Laurence Olivier's Hamlet (1948). Broadening its scope further, Universal-International branched out into the lucrative non-theatrical field, buying a majority stake in home-movie dealer Castle Films in 1947, and taking the company over entirely in 1951. For three decades, Castle would offer "highlights" reels from the Universal film library to home-movie enthusiasts and collectors. Goetz licensed Universal's pre–Universal-International film library to Jack Broeder's Realart Pictures for cinema re-release but Realart was not allowed to show the films on television.

Question: In 1947, what company did Universal buy a stake in?
Ans: Castle Films


Article: The Berggarten is an important European botanical garden.[citation needed] Some points of interest are the Tropical House, the Cactus House, the Canary House and the Orchid House, which hosts one of the world's biggest collection of orchids, and free-flying birds and butterflies. Near the entrance to the Berggarten is the historic Library Pavillon. The Mausoleum of the Guelphs is also located in the Berggarten. Like the Great Garden, the Berggarten also consists of several parts, for example the Paradies and the Prairie Garden. There is also the Sea Life Centre Hanover, which is the first tropical aquarium in Germany.[citation needed]

Question: What is the Berggarten?
Ans:
European botanical garden