instruction:
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
question:
However a log-periodic dipole array consists of a number of dipole elements of different lengths in order to obtain a somewhat directional antenna having an extremely wide bandwidth: these are frequently used for television reception in fringe areas. The dipole antennas composing it are all considered "active elements" since they are all electrically connected together (and to the transmission line). On the other hand, a superficially similar dipole array, the Yagi-Uda Antenna (or simply "Yagi"), has only one dipole element with an electrical connection; the other so-called parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth. The Yagi antenna has similar looking parasitic dipole elements but which act differently due to their somewhat different lengths. There may be a number of so-called "directors" in front of the active element in the direction of propagation, and usually a single (but possibly more) "reflector" on the opposite side of the active element.
answer:
What type of antenna formation is made up of multiple dipole elements of varying lengths?


question:
The London Fire Brigade is the statutory fire and rescue service for Greater London. It is run by the London Fire and Emergency Planning Authority and is the third largest fire service in the world. National Health Service ambulance services are provided by the London Ambulance Service (LAS) NHS Trust, the largest free-at-the-point-of-use emergency ambulance service in the world. The London Air Ambulance charity operates in conjunction with the LAS where required. Her Majesty's Coastguard and the Royal National Lifeboat Institution operate on the River Thames, which is under the jurisdiction of the Port of London Authority from Teddington Lock to the sea.
answer:
What area of the River Thames does the Port of London Authority's jurisdiction cover?


question:
One of the more prominent contestants this year was Chris Medina, whose story of caring for his brain-damaged fiancée received widespread coverage. Medina was cut in the Top 40 round. Casey Abrams, who suffers from ulcerative colitis, was hospitalized twice and missed the Top 13 result show. The judges used their one save on Abrams on the Top 11, and as a result this was the first season that 11 finalists went on tour instead of 10. In the following week, Naima Adedapo and Thia Megia were both eliminated the following week.
answer:
Which contestant had a fiancé that had suffered brain damage?