Article: Most electrification systems use overhead wires, but third rail is an option up to about 1,200 V. Third rail systems exclusively use DC distribution. The use of AC is not feasible because the dimensions of a third rail are physically very large compared with the skin depth that the alternating current penetrates to (0.3 millimetres or 0.012 inches) in a steel rail). This effect makes the resistance per unit length unacceptably high compared with the use of DC. Third rail is more compact than overhead wires and can be used in smaller-diameter tunnels, an important factor for subway systems.

Question: What is more prefferable for subway lines?
Ans: Third rail

Article: The main mineral resource known on the continent is coal. It was first recorded near the Beardmore Glacier by Frank Wild on the Nimrod Expedition, and now low-grade coal is known across many parts of the Transantarctic Mountains. The Prince Charles Mountains contain significant deposits of iron ore. The most valuable resources of Antarctica lie offshore, namely the oil and natural gas fields found in the Ross Sea in 1973. Exploitation of all mineral resources is banned until 2048 by the Protocol on Environmental Protection to the Antarctic Treaty.

Question: What expedition discovered coal on Antarctica?
Ans: Nimrod Expedition

Article: At a minimum, HDTV has twice the linear resolution of standard-definition television (SDTV), thus showing greater detail than either analog television or regular DVD. The technical standards for broadcasting HDTV also handle the 16:9 aspect ratio images without using letterboxing or anamorphic stretching, thus increasing the effective image resolution.

Question: HDTV handles what aspect ratio without using letterboxing or anamorphic stretching?
Ans: 16:9

Article: IBM also holds the SmartCamp program globally. The program searches for fresh start-up companies that IBM can partner with to solve world problems. IBM holds 17 SmartCamp events around the world. Since July 2011, IBM has partnered with Pennies, the electronic charity box, and produced a software solution for IBM retail customers that provides an easy way to donate money when paying in-store by credit or debit card. Customers donate just a few pence (1p-99p) a time and every donation goes to UK charities.

Question: What is the name of the program that IBM uses to search for new start-up companies to solve world problems?
Ans:
SmartCamp