Context and question: In the last two decades, photovoltaics (PV), also known as solar PV, has evolved from a pure niche market of small scale applications towards becoming a mainstream electricity source. A solar cell is a device that converts light directly into electricity using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. In 1931 a German engineer, Dr Bruno Lange, developed a photo cell using silver selenide in place of copper oxide. Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the crystalline silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4.5–6%. By 2012 available efficiencies exceed 20% and the maximum efficiency of research photovoltaics is over 40%.
Who created the crystalline silicon solar cell?
Answer: Gerald Pearson, Calvin Fuller and Daryl Chapin
Context and question: Jefferson and James Madison's conceptions of separation have long been debated. Jefferson refused to issue Proclamations of Thanksgiving sent to him by Congress during his presidency, though he did issue a Thanksgiving and Prayer proclamation as Governor of Virginia. Madison issued four religious proclamations while President, but vetoed two bills on the grounds they violated the first amendment. On the other hand, both Jefferson and Madison attended religious services at the Capitol. Years before the ratification of the Constitution, Madison contended "Because if Religion be exempt from the authority of the Society at large, still less can it be subject to that of the Legislative Body." After retiring from the presidency, Madison wrote of "total separation of the church from the state." " "Strongly guarded as is the separation between Religion & Govt in the Constitution of the United States," Madison wrote, and he declared, "practical distinction between Religion and Civil Government is essential to the purity of both, and as guaranteed by the Constitution of the United States." In a letter to Edward Livingston Madison further expanded, "We are teaching the world the great truth that Govts. do better without Kings & Nobles than with them. The merit will be doubled by the other lesson that Religion flourishes in greater purity, without than with the aid of Govt." Madison's original draft of the Bill of Rights had included provisions binding the States, as well as the Federal Government, from an establishment of religion, but the House did not pass them.[citation needed]
What did Jefferson approve to issue, when it was sent to him by Congress during his presidency?
Answer: unanswerable
Context and question: Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog. The engineer Tommy Flowers, working at the Post Office Research Station in London in the 1930s, began to explore the possible use of electronics for the telephone exchange. Experimental equipment that he built in 1934 went into operation 5 years later, converting a portion of the telephone exchange network into an electronic data processing system, using thousands of vacuum tubes. In the US, John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed and tested the Atanasoff–Berry Computer (ABC) in 1942, the first "automatic electronic digital computer". This design was also all-electronic and used about 300 vacuum tubes, with capacitors fixed in a mechanically rotating drum for memory.
Where did the engineer Tommy Flowers work at during the 1930s?
Answer:
Post Office Research Station