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The spectrum emitted by a blackbody radiator at temperatures of incandescent bulbs does not match the sensitivity characteristics of the human eye; the light emitted does not appear white, and most is not in the range of wavelengths at which the eye is most sensitive. Tungsten filaments radiate mostly infrared radiation at temperatures where they remain solid below 3,695 K (3,422 C; 6,191 F). Donald L. Klipstein explains it this way: "An ideal thermal radiator produces visible light most efficiently at temperatures around 6,300 C (6,600 K; 11,400 F). Even at this high temperature, a lot of the radiation is either infrared or ultraviolet, and the theoretical luminous efficacy (LER) is 95 lumens per watt." No known material can be used as a filament at this ideal temperature, which is hotter than the sun's surface. An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point.
What is the lower limit for LER of an incandescent lamp?
A: unanswerable

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English Freemasonry spread to France in the 1720s, first as lodges of expatriates and exiled Jacobites, and then as distinctively French lodges which still follow the ritual of the Moderns. From France and England, Freemasonry spread to most of Continental Europe during the course of the 18th century. The Grande Loge de France formed under the Grand Mastership of the Duke of Clermont, who exercised only nominal authority. His successor, the Duke of Orleans, reconstituted the central body as the Grand Orient de France in 1773. Briefly eclipsed during the French Revolution, French Freemasonry continued to grow in the next century.
Who was the successor to the Grand Mastership of The Duke of Clermont?
A: the Duke of Orleans

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The Tuvaluan language and English are the national languages of Tuvalu. Tuvaluan is of the Ellicean group of Polynesian languages, distantly related to all other Polynesian languages such as Hawaiian, Maori, Tahitian, Samoan and Tongan. It is most closely related to the languages spoken on the Polynesian outliers in Micronesia and northern and central Melanesia. The language has borrowed from the Samoan language, as a consequence of Christian missionaries in the late 19th and early 20th centuries being predominantly Samoan.
Besides English, what is the national language of Tuvalu?
A: Tuvaluan

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Executive power is vested, with exceptions and qualifications, in the President. By law (Section 2.) the president becomes the Commander in Chief of the Army and Navy, Militia of several states when called into service, has power to make treaties and appointments to office "with the Advice and Consent of the Senate," receive Ambassadors and Public Ministers, and "take care that the laws be faithfully executed" (Section 3.) By using these words, the Constitution does not require the president to personally enforce the law; rather, officers subordinate to the president may perform such duties. The Constitution empowers the president to ensure the faithful execution of the laws made by Congress and approved by the President. Congress may itself terminate such appointments, by impeachment, and restrict the president. Bodies such as the War Claims Commission, the Interstate Commerce Commission and the Federal Trade Commissionall quasi-judicialoften have direct Congressional oversight.
Which branches of the national military does the U.S. president command?
A:
Army and Navy