Input: Green
Green can communicate safety to proceed, as in traffic lights. Green and red were standardized as the colors of international railroad signals in the 19th century. The first traffic light, using green and red gas lamps, was erected in 1868 in front of the Houses of Parliament in London. It exploded the following year, injuring the policeman who operated it. In 1912, the first modern electric traffic lights were put up in Salt Lake City, Utah. Red was chosen largely because of its high visibility, and its association with danger, while green was chosen largely because it could not be mistaken for red. Today green lights universally signal that a system is turned on and working as it should. In many video games, green signifies both health and completed objectives, opposite red.

When were green and red standardized as the colors of international railroad signs?
Output: 19th century

Input: Mandolin
Numerous modern mandolin makers build instruments that largely replicate the Gibson F-5 Artist models built in the early 1920s under the supervision of Gibson acoustician Lloyd Loar. Original Loar-signed instruments are sought after and extremely valuable. Other makers from the Loar period and earlier include Lyon and Healy, Vega and Larson Brothers. Some notable modern American carved mandolin manufacturers include, in addition to Kay, Gibson, Weber, Monteleone and Collings. Mandolins from other countries include The Loar (China), Santa, Rosa (China), Michael Kelly (Korea), Eastman (China), Kentucky (China), Heiden (Canada), Gilchrist (Australia) and Morgan Monroe (China).

What style of Gisbon Mandolin was largely replicated?
Output: Gibson F-5

Input: Antenna (radio)
However loss resistance will generally affect the feedpoint impedance, adding to its resistive (real) component. That resistance will consist of the sum of the radiation resistance Rr and the loss resistance Rloss. If an rms current I is delivered to the terminals of an antenna, then a power of I2Rr will be radiated and a power of I2Rloss will be lost as heat. Therefore, the efficiency of an antenna is equal to Rr / (Rr + Rloss). Of course only the total resistance Rr + Rloss can be directly measured.

What equation an determine an antennas effectiveness?
Output: Rr / (Rr + Rloss)

Input: Mandolin
The mandolin's popularity in the United States was spurred by the success of a group of touring young European musicians known as the Estudiantina Figaro, or in the United States, simply the "Spanish Students." The group landed in the U.S. on January 2, 1880 in New York City, and played in Boston and New York to wildly enthusiastic crowds. Ironically, this ensemble did not play mandolins but rather bandurrias, which are also small, double-strung instruments that resemble the mandolin. The success of the Figaro Spanish Students spawned other groups who imitated their musical style and costumes. An Italian musician, Carlo Curti, hastily started a musical ensemble after seeing the Figaro Spanish Students perform; his group of Italian born Americans called themselves the "Original Spanish Students," counting on the American public to not know the difference between the Spanish bandurrias and Italian mandolins. The imitators' use of mandolins helped to generate enormous public interest in an instrument previously relatively unknown in the United States.

What group was inspired by the Estudiantina Figaro? 
Output:
Original Spanish Students