Article: The radiation pattern and even the driving point impedance of an antenna can be influenced by the dielectric constant and especially conductivity of nearby objects. For a terrestrial antenna, the ground is usually one such object of importance. The antenna's height above the ground, as well as the electrical properties (permittivity and conductivity) of the ground, can then be important. Also, in the particular case of a monopole antenna, the ground (or an artificial ground plane) serves as the return connection for the antenna current thus having an additional effect, particularly on the impedance seen by the feed line.

Question: What does the artificial ground plane do for the antenna current?
Ans: return connection

Article: In the late 12th-century, a school of polyphony was established at the Notre-Dame. A group of Parisian aristocrats, known as Trouveres, became known for their poetry and songs. Troubadors were also popular. During the reign of Francois I, the lute became popular in the French court, and a national musical printing house was established. During the Renaissance era, the French Boleroroyals "disported themselves in masques, ballets, allegorical dances, recitals, and opera and comedy". Baroque-era composers include Jean-Baptiste Lully, Jean-Philippe Rameau, and Francois Couperin and were popular. The Conservatoire de Musique de Paris was founded in 1795. By 1870, Paris had become an important centre for symphony, ballet and operatic music. Romantic-era composers (in Paris) include Hector Berlioz (La Symphonie fantastique), Charles Gounod (Faust), Camille Saint-Saens (Samson et Delilah), Leo Delibes (Lakme) and Jules Massenet (Thais), among others. Georges Bizet's Carmen premiered 3 March 1875. Carmen has since become one of the most popular and frequently-performed operas in the classical canon; Impressionist composers Claude Debussy ((La Mer) and Maurice Ravel (Bolero) also made significant contributions to piano (Clair de lune, Miroirs), orchestra, opera (Palleas et Melisande), and other musical forms. Foreign-born composers have made their homes in Paris and have made significant contributions both with their works and their influence. They include Frederic Chopin (Poland), Franz Liszt (Hungary), Jacques Offenbach (Germany), and Igor Stravinsky (Russia).

Question: in what century was a school of polyphony established at Notre Dame?
Ans: 12th

Article: The divisions between all these groups are approximate and their boundaries are not always clear. The Mizrahim for example, are a heterogeneous collection of North African, Central Asian, Caucasian, and Middle Eastern Jewish communities that are no closer related to each other than they are to any of the earlier mentioned Jewish groups. In modern usage, however, the Mizrahim are sometimes termed Sephardi due to similar styles of liturgy, despite independent development from Sephardim proper. Thus, among Mizrahim there are Egyptian Jews, Iraqi Jews, Lebanese Jews, Kurdish Jews, Libyan Jews, Syrian Jews, Bukharian Jews, Mountain Jews, Georgian Jews, Iranian Jews and various others. The Teimanim from Yemen are sometimes included, although their style of liturgy is unique and they differ in respect to the admixture found among them to that found in Mizrahim. In addition, there is a differentiation made between Sephardi migrants who established themselves in the Middle East and North Africa after the expulsion of the Jews from Spain and Portugal in the 1490s and the pre-existing Jewish communities in those regions.

Question: In modern usage, why is Mizrahim sometimes termed Sephardi?
Ans: due to similar styles of liturgy

Article: Yet another influential philosopher who had an influence on modern philosophy was Ibn Tufail. His philosophical novel, Hayy ibn Yaqdha, translated into Latin as Philosophus Autodidactus in 1671, developed the themes of empiricism, tabula rasa, nature versus nurture, condition of possibility, materialism, and Molyneux's problem. European scholars and writers influenced by this novel include John Locke, Gottfried Leibniz, Melchisedech Thevenot, John Wallis, Christiaan Huygens, George Keith, Robert Barclay, the Quakers, and Samuel Hartlib.

Question: Who wrote Hayy ibn Yaqdha?
Ans:
Ibn Tufail