Problem: Please answer a question about the following article about Railway electrification system:
Motors have very little room for electrical insulation so they generally have low voltage ratings. Because transformers (prior to the development of power electronics) cannot step down DC voltages, trains were supplied with a relatively low DC voltage that the motors can use directly. The most common DC voltages are listed in the previous section. Third (and fourth) rail systems almost always use voltages below 1 kV for safety reasons while overhead wires usually use higher voltages for efficiency. ("Low" voltage is relative; even 600 V can be instantly lethal when touched.)
Is "low" voltage used by trains safe for people?
A: lethal
Problem: Please answer a question about the following article about Premier League:
There has been an increasing gulf between the Premier League and the Football League. Since its split with the Football League, many established clubs in the Premier League have managed to distance themselves from their counterparts in lower leagues. Owing in large part to the disparity in revenue from television rights between the leagues, many newly promoted teams have found it difficult to avoid relegation in their first season in the Premier League. In every season except 2001–02 and 2011–12, at least one Premier League newcomer has been relegated back to the Football League. In 1997–98 all three promoted clubs were relegated at the end of the season.
In every season but 2001-02 and 2011-12, at least how many Premier League teams have been relegated?
A: one
Problem: Please answer a question about the following article about Beer:
The earliest known chemical evidence of barley beer dates to circa 3500–3100 BC from the site of Godin Tepe in the Zagros Mountains of western Iran. Some of the earliest Sumerian writings contain references to beer; examples include a prayer to the goddess Ninkasi, known as "The Hymn to Ninkasi", which served as both a prayer as well as a method of remembering the recipe for beer in a culture with few literate people, and the ancient advice (Fill your belly. Day and night make merry) to Gilgamesh, recorded in the Epic of Gilgamesh, by the ale-wife Siduri may, at least in part, have referred to the consumption of beer. The Ebla tablets, discovered in 1974 in Ebla, Syria, show that beer was produced in the city in 2500 BC. A fermented beverage using rice and fruit was made in China around 7000 BC. Unlike sake, mould was not used to saccharify the rice (amylolytic fermentation); the rice was probably prepared for fermentation by mastication or malting.
In what country was the earliest chemical evidence of barley beer found?
A: Iran
Problem: Please answer a question about the following article about Antenna (radio):
This is fortunate, since antennas at lower frequencies which are not rather large (a good fraction of a wavelength in size) are inevitably inefficient (due to the small radiation resistance Rr of small antennas). Most AM broadcast radios (except for car radios) take advantage of this principle by including a small loop antenna for reception which has an extremely poor efficiency. Using such an inefficient antenna at this low frequency (530–1650 kHz) thus has little effect on the receiver's net performance, but simply requires greater amplification by the receiver's electronics. Contrast this tiny component to the massive and very tall towers used at AM broadcast stations for transmitting at the very same frequency, where every percentage point of reduced antenna efficiency entails a substantial cost.
What is added to to increase ability for reception?
A:
small loop antenna