Problem: Uranium:

Uranium-238 is the most stable isotope of uranium, with a half-life of about 4.468109 years, roughly the age of the Earth. Uranium-235 has a half-life of about 7.13108 years, and uranium-234 has a half-life of about 2.48105 years. For natural uranium, about 49% of its alpha rays are emitted by each of 238U atom, and also 49% by 234U (since the latter is formed from the former) and about 2.0% of them by the 235U. When the Earth was young, probably about one-fifth of its uranium was uranium-235, but the percentage of 234U was probably much lower than this.

What fraction of the Earth's uranium was uranium-237 during the Earth's youth?
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A: unanswerable

Problem: Antenna (radio):

An antenna lead-in is the transmission line (or feed line) which connects the antenna to a transmitter or receiver. The antenna feed may refer to all components connecting the antenna to the transmitter or receiver, such as an impedance matching network in addition to the transmission line. In a so-called aperture antenna, such as a horn or parabolic dish, the "feed" may also refer to a basic antenna inside the entire system (normally at the focus of the parabolic dish or at the throat of a horn) which could be considered the one active element in that antenna system. A microwave antenna may also be fed directly from a waveguide in place of a (conductive) transmission line.

What are the type of antennas used with satellite television called?
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A: aperture antenna

Problem: Carnival:

The most famous groups are the chirigotas, choirs and comparsas. The chirigotas are well known witty, satiric popular groups who sing about politics, new times and household topics, wearing the same costume, which they prepare for the whole year. The Choirs (coros) are wider groups that go on open carts through the streets singing with an orchestra of guitars and lutes. Their signature piece is the "Carnival Tango", alternating comical and serious repertory. The comparsas are the serious counterpart of the chirigota in Cadiz, and the poetic lyrics and the criticism are their main ingredients. They have a more elaborated polyphony that is easily recognizable by the typical countertenor voice.

The chirigotas, choirs and comparsas are the most famous of what?
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A: groups

Problem: Tucson, Arizona:

The Tucson metro area is served by many local television stations and is the 68th largest designated market area (DMA) in the U.S. with 433,310 homes (0.39% of the total U.S.). It is limited to the three counties of southeastern Arizona (Pima, Santa Cruz, and Cochise) The major television networks serving Tucson are: KVOA 4 (NBC), KGUN 9 (ABC), KMSB-TV 11 (Fox), KOLD-TV 13 (CBS), KTTU 18 (My Network TV) and KWBA 58 (The CW). KUAT-TV 6 is a PBS affiliate run by the University of Arizona (as is sister station KUAS 27).

What is Tucson's ABC station?
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A:
KGUN 9