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 first solar cell?
Answer: Charles Fritts
Context and question: When not celebrating Mass but still serving a liturgical function, such as the semiannual Urbi et Orbi papal blessing, some Papal Masses and some events at Ecumenical Councils, cardinal deacons can be recognized by the dalmatics they would don with the simple white mitre (so called mitra simplex).
How are Cardinal deacons recognized at Masses?
Answer: unanswerable
Context and question: Following the death in 1473 of James II, the last Lusignan king, the Republic of Venice assumed control of the island, while the late king's Venetian widow, Queen Catherine Cornaro, reigned as figurehead. Venice formally annexed the Kingdom of Cyprus in 1489, following the abdication of Catherine. The Venetians fortified Nicosia by building the Venetian Walls, and used it as an important commercial hub. Throughout Venetian rule, the Ottoman Empire frequently raided Cyprus. In 1539 the Ottomans destroyed Limassol and so fearing the worst, the Venetians also fortified Famagusta and Kyrenia.
In what year did the Ottomans destroy Limassol?
Answer:
1539