Question: The light from LEDs can be modulated very quickly so they are used extensively in optical fiber and free space optics communications. This includes remote controls, such as for TVs, VCRs, and LED Computers, where infrared LEDs are often used. Opto-isolators use an LED combined with a photodiode or phototransistor to provide a signal path with electrical isolation between two circuits. This is especially useful in medical equipment where the signals from a low-voltage sensor circuit (usually battery-powered) in contact with a living organism must be electrically isolated from any possible electrical failure in a recording or monitoring device operating at potentially dangerous voltages. An optoisolator also allows information to be transferred between circuits not sharing a common ground potential.
Try to answer this question if possible: What is an example of a device that uses not free space optic communications?
Answer: unanswerable
Question: Hospitals in Liberia include the John F. Kennedy Medical Center in Monrovia and several others. Life expectancy in Liberia is estimated to be 57.4 years in 2012. With a fertility rate of 5.9 births per woman, the maternal mortality rate stood at 990 per 100,000 births in 2010. A number of highly communicable diseases are widespread, including tuberculosis, diarrheal diseases and malaria. In 2007, the HIV infection rates stood at 2% of the population aged 1549 whereas the incidence of tuberculosis was 420 per 100,000 people in 2008. Approximately 58.2% 66% of women are estimated to have undergone female genital mutilation.
Try to answer this question if possible: What were the HIV infection rates in 2007?
Answer: 2%
Question: Steven Waldman notes that; "The evangelicals provided the political muscle for the efforts of Madison and Jefferson, not merely because they wanted to block official churches but because they wanted to keep the spiritual and secular worlds apart." "Religious freedom resulted from an alliance of unlikely partners," writes the historian Frank Lambert in his book The Founding Fathers and the Place of Religion in America. "New Light evangelicals such as Isaac Bachus and John Leland joined forces with Deists and skeptics such as James Madison and Thomas Jefferson to fight for a complete separation of church and state."
Try to answer this question if possible: What did evangelicals want to keep apart?
Answer: the spiritual and secular worlds
Question: Arsenal's longest-running and deepest rivalry is with their nearest major neighbours, Tottenham Hotspur; matches between the two are referred to as North London derbies. Other rivalries within London include those with Chelsea, Fulham and West Ham United. In addition, Arsenal and Manchester United developed a strong on-pitch rivalry in the late 1980s, which intensified in recent years when both clubs were competing for the Premier League title so much so that a 2003 online poll by the Football Fans Census listed Manchester United as Arsenal's biggest rivals, followed by Tottenham and Chelsea. A 2008 poll listed the Tottenham rivalry as more important.
Try to answer this question if possible: In what year was West Ham United founded?
Answer:
unanswerable