Problem: Given the question: Question: "Which of the following does not measure the amount of usable light: luminous efficacy, directionality or wall-plug efficiency?" Context: "An important property of light fixtures is the luminous efficacy or wall-plug efficiency, meaning the amount of usable light emanating from the fixture per used energy, usually measured in lumen per watt. A fixture using replaceable light sources can also have its efficiency quoted as the percentage of light passed from the "bulb" to the surroundings. The more transparent the lighting fixture is, the higher efficacy. Shading the light will normally decrease efficacy but increase the directionality and the visual comfort probability." Answer:
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The answer is:
directionality

Problem: Given the question: Question: "Electromagnetic radiation is a drawback with its' use?" Context: "There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union." Answer:
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The answer is:
AC

Problem: Given the question: Question: "What is rapping?" Context: "Beginning with the advent of beat match DJing, in which Bronx DJs (Disc Jockeys) including Grandmaster Flash, Afrika Bambaataa and DJ Kool Herc extended the breaks of funk records, a major new musical genre emerged that sought to isolate the percussion breaks of hit funk, disco and soul songs. As hip hop's popularity grew, performers began speaking ("rapping") in sync with the beats, and became known as MCs or emcees. The Herculoids, made up of Herc, Coke La Rock, and DJ Clark Kent, were the earliest to gain major fame. The Bronx is referred to in hip-hop slang as "The Boogie Down Bronx", or just "The Boogie Down". This was hip-hop pioneer KRS-One's inspiration for his thought provoking group BDP, or Boogie Down Productions, which included DJ Scott La Rock. Newer hip hop artists from the Bronx include Big Pun, Lord Toriq and Peter Gunz, Camp Lo, Swizz Beatz, Drag-On, Fat Joe, Terror Squad and Corey Gunz." Answer:
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The answer is:
speaking ("rapping") in sync with the beats