Q: Extract the answer to the question from the following context. Question: Power factor problems are 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.
A: AC

Q: Extract the answer to the question from the following context. Question: Which of the following is not a characteristic of intermetallic compounds: defined stoichiometry, bond types, or crystal structure? Context: An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle for information on classifying bonding in binary compounds).
A: bond types

Q: Extract the answer to the question from the following context. Question: What can pain do? Context: Pain is the most common reason for physician consultation in most developed countries. It is a major symptom in many medical conditions, and can interfere with a person's quality of life and general functioning. Psychological factors such as social support, hypnotic suggestion, excitement, or distraction can significantly affect pain's intensity or unpleasantness. In some arguments put forth in physician-assisted suicide or euthanasia debates, pain has been used as an argument to permit terminally ill patients to end their lives.
A: It is a major symptom in many medical conditions, and can interfere with a person's quality of life and general functioning. Psychological factors such as social support, hypnotic suggestion, excitement, or distraction can significantly affect pain's intensity or unpleasantness

Q: Extract the answer to the question from the following context. Question: Who does NOT live at 10 Downing Street, John Bright or the Prime Minister? Context: London is the seat of the Government of the United Kingdom. Many government departments are based close to the Palace of Westminster, particularly along Whitehall, including the Prime Minister's residence at 10 Downing Street. The British Parliament is often referred to as the "Mother of Parliaments" (although this sobriquet was first applied to England itself by John Bright) because it has been the model for most other parliamentary systems. There are 73 Members of Parliament (MPs) from London, who correspond to local parliamentary constituencies in the national Parliament. As of May 2015, 45 are from the Labour Party, 27 are Conservatives, and one is a Liberal Democrat.
A:
John Bright