Problem: Solar energy:

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 the 1880s, who constructed the first solar cell?
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A: Charles Fritts

Problem: With French, Belgian and Portuguese activity in the lower Congo River region undermining orderly incursion of tropical Africa, the Berlin Conference of 188485 was held to regulate the competition between the European powers in what was called the "Scramble for Africa" by defining "effective occupation" as the criterion for international recognition of territorial claims. The scramble continued into the 1890s, and caused Britain to reconsider its decision in 1885 to withdraw from Sudan. A joint force of British and Egyptian troops defeated the Mahdist Army in 1896, and rebuffed a French attempted invasion at Fashoda in 1898. Sudan was nominally made an Anglo-Egyptian Condominium, but a British colony in reality.
Where did France try to invade in 1898?
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Answer: Fashoda

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
One elector in Minnesota cast a ballot for president with the name of "John Ewards" [sic] written on it. The Electoral College officials certified this ballot as a vote for John Edwards for president. The remaining nine electors cast ballots for John Kerry. All ten electors in the state cast ballots for John Edwards for vice president (John Edwards's name was spelled correctly on all ballots for vice president). This was the first time in U.S. history that an elector had cast a vote for the same person to be both president and vice president; another faithless elector in the 1800 election had voted twice for Aaron Burr, but under that electoral system only votes for the president's position were cast, with the runner-up in the Electoral College becoming vice president (and the second vote for Burr was discounted and re-assigned to Thomas Jefferson in any event, as it violated Electoral College rules).
How many times had Aaron Burr run for office in the past?
A: unanswerable

Context and question: General Electric heavily contaminated the Hudson River with polychlorinated biphenyls (PCBs) between 1947-77. This pollution caused a range of harmful effects to wildlife and people who eat fish from the river or drink the water. In response to this contamination, activists protested in various ways. Musician Pete Seeger founded the Hudson River Sloop Clearwater and the Clearwater Festival to draw attention to the problem. The activism led to the site being designated by the EPA as one of the superfund sites requiring extensive cleanup. Other sources of pollution, including mercury contamination and sewage dumping, have also contributed to problems in the Hudson River watershed.
In what year did sewage dumping in the Hudson River become a problem?
Answer: unanswerable

Question: With preceding legal institutions abolished, Gaddafi envisioned the Jamahiriya as following the Qur'an for legal guidance, adopting sharia law; he proclaimed "man-made" laws unnatural and dictatorial, only permitting Allah's law. Within a year he was backtracking, announcing that sharia was inappropriate for the Jamahiriya because it guaranteed the protection of private property, contravening The Green Book's socialism. His emphasis on placing his own work on a par with the Qur'an led conservative clerics to accuse him of shirk, furthering their opposition to his regime. In July, a border war broke out with Egypt, in which the Egyptians defeated Libya despite their technological inferiority. The conflict lasted one week before both sides agreed to sign a peace treaty that was brokered by several Arab states. That year, Gaddafi was invited to Moscow by the Soviet government in recognition of their increasing commercial relationship.
Is there an answer to this question: What book did the Jamahiriya look to for legal advice?

Answer: Qur'an

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The original NAS Bermuda on the west side of the island, a seaplane base until the mid-1960s, was designated as the Naval Air Station Bermuda Annex. It provided optional anchorage and/or dockage facilities for transiting US Navy, US Coast Guard and NATO vessels, depending on size. An additional US Navy compound known as Naval Facility Bermuda (NAVFAC Bermuda), a SOSUS station, was located to the west of the Annex near a Canadian Forces communications facility. Although leased for 99 years, US forces withdrew in 1995, as part of the wave of base closures following the end of the Cold War.
What did US forces do in 1999?
A:
unanswerable