QUES: 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 4.56%. By 2012 available efficiencies exceed 20% and the maximum efficiency of research photovoltaics is over 40%.

In what year was the crystalline silicon solar cell constructed?
What is the answer?
ANS: 1954
QUES: In March 1912, in Chihuahua, Gen. Pascual Orozco revolted. Immediately President Francisco Madero commanded Gen. Victoriano Huerta of the Federal Army, to put down the Orozco revolt. The governor of Chihuahua mobilized the state militia led by Colonel Pancho Villa to supplement General Huerta. By June, Villa notified Huerta that the Orozco revolt had been put down and that the militia would consider themselves no longer under Huerta's command and would depart. Huerta became furious and ordered that Villa be executed. Raul Madero, Madero's brother, intervened to save Villa's life. Jailed in Mexico City, Villa fled to the United States. Madero's time as leader was short-lived, ended by a coup d'etat in 1913 led by Gen. Victoriano Huerta; Orozco sided with Huerta, and Huerta made him one of his generals.

Who notified Huerta the revolt had been put down?
What is the answer?
ANS: Villa
QUES: The Orthodox nobles' rights were nominally equal to those enjoyed by Polish and Lithuanian nobility, but there was a cultural pressure to convert to Catholicism, that was greatly eased in 1596 by the Union of Brest. See for example careers of Senator Adam Kisiel and Jerzy Franciszek Kulczycki.

What other rights were equal to orthodox nobles?
What is the answer?
ANS:
Polish and Lithuanian nobility