Context and question: Each trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In a multi-layer board one entire layer may be mostly solid copper to act as a ground plane for shielding and power return. For microwave circuits, transmission lines can be laid out in the form of stripline and microstrip with carefully controlled dimensions to assure a consistent impedance. In radio-frequency and fast switching circuits the inductance and capacitance of the printed circuit board conductors become significant circuit elements, usually undesired; but they can be used as a deliberate part of the circuit design, obviating the need for additional discrete components.
What consists of a wide, curved part of copper foil?
Answer: unanswerable
Context and question: One of the first demonstrations of the ability for telecommunications to help sign language users communicate with each other occurred when AT&T's videophone (trademarked as the "Picturephone") was introduced to the public at the 1964 New York World's Fair –two deaf users were able to communicate freely with each other between the fair and another city. Various universities and other organizations, including British Telecom's Martlesham facility, have also conducted extensive research on signing via videotelephony. The use of sign language via videotelephony was hampered for many years due to the difficulty of its use over slow analogue copper phone lines, coupled with the high cost of better quality ISDN (data) phone lines. Those factors largely disappeared with the introduction of more efficient video codecs and the advent of lower cost high-speed ISDN data and IP (Internet) services in the 1990s.
In what year was AT&T's "Picturephone" device introduced?
Answer: 1964
Context and question: Norfolk Island is located in the South Pacific Ocean, east of the Australian mainland. Norfolk Island is the main island of the island group the territory encompasses and is located at 29°02′S 167°57′E﻿ / ﻿29.033°S 167.950°E﻿ / -29.033; 167.950. It has an area of 34.6 square kilometres (13.4 sq mi), with no large-scale internal bodies of water and 32 km (20 mi) of coastline. The island's highest point is Mount Bates (319 metres (1,047 feet) above sea level), located in the northwest quadrant of the island. The majority of the terrain is suitable for farming and other agricultural uses. Phillip Island, the second largest island of the territory, is located at 29°07′S 167°57′E﻿ / ﻿29.117°S 167.950°E﻿ / -29.117; 167.950, seven kilometres (4.3 miles) south of the main island.
What part of the Pacific Ocean is Norfolk Island located?
Answer:
South