Q: I know that the answer to the question "Electromagnetic radiation is a drawback with its' use?" is in "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.". Can you tell me what it is?
A: AC

Q: I know that the answer to the question "Which was produced before 2005, Mona Lisa Smile or Indiana Jones and the Kingdom of the Crystal Skull?" is in "Several recent movies have been filmed in New Haven, including Mona Lisa Smile (2003), with Julia Roberts, The Life Before Her Eyes (2007), with Uma Thurman, and Indiana Jones and the Kingdom of the Crystal Skull (2008) directed by Steven Spielberg and starring Harrison Ford, Cate Blanchett and Shia LaBeouf. The filming of Crystal Skull involved an extensive chase sequence through the streets of New Haven. Several downtown streets were closed to traffic and received a "makeover" to look like streets of 1957, when the film is set. 500 locals were cast as extras for the film. In Everybody's Fine (2009), Robert De Niro has a close encounter in what is supposed to be the Denver train station; the scene was filmed in New Haven's Union Station.". Can you tell me what it is?
A: Mona Lisa Smile

Q: I know that the answer to the question "What was the result of the defeat?" is in "After the Dambusters raid in 1943 an entirely new system was developed that was required to knock down any low-flying aircraft with a single hit. The first attempt to produce such a system used a 50 mm gun, but this proved inaccurate and a new 55 mm gun replaced it. The system used a centralised control system including both search and targeting radar, which calculated the aim point for the guns after considering windage and ballistics, and then sent electrical commands to the guns, which used hydraulics to point themselves at high speeds. Operators simply fed the guns and selected the targets. This system, modern even by today's standards, was in late development when the war ended.". Can you tell me what it is?
A: an entirely new system was developed

Q: I know that the answer to the question "what was the last word in the passage?" is in "DST has mixed effects on health. In societies with fixed work schedules it provides more afternoon sunlight for outdoor exercise. It alters sunlight exposure; whether this is beneficial depends on one's location and daily schedule, as sunlight triggers vitamin D synthesis in the skin, but overexposure can lead to skin cancer. DST may help in depression by causing individuals to rise earlier, but some argue the reverse. The Retinitis Pigmentosa Foundation Fighting Blindness, chaired by blind sports magnate Gordon Gund, successfully lobbied in 1985 and 2005 for US DST extensions.". Can you tell me what it is?
A:
extensions