Problem: Please answer a question about the following article about Printed circuit board:
Development of the methods used in modern printed circuit boards started early in the 20th century. In 1903, a German inventor, Albert Hanson, described flat foil conductors laminated to an insulating board, in multiple layers. Thomas Edison experimented with chemical methods of plating conductors onto linen paper in 1904. Arthur Berry in 1913 patented a print-and-etch method in Britain, and in the United States Max Schoop obtained a patent to flame-spray metal onto a board through a patterned mask. Charles Ducas in 1927 patented a method of electroplating circuit patterns.
Who obtained a patent in 1927 for his method of electroplating circuit patterns?
A: Charles Ducas
Problem: Please answer a question about the following article about Uranium:
Natural uranium consists of three major isotopes: uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three are radioactive, emitting alpha particles, with the exception that all three of these isotopes have small probabilities of undergoing spontaneous fission, rather than alpha emission. There are also five other trace isotopes: uranium-239, which is formed when 238U undergoes spontaneous fission, releasing neutrons that are captured by another 238U atom; uranium-237, which is formed when 238U captures a neutron but emits two more, which then decays to neptunium-237; uranium-233, which is formed in the decay chain of that neptunium-237; and finally, uranium-236 and -240, which appear in the decay chain of primordial plutonium-244. It is also expected that thorium-232 should be able to undergo double beta decay, which would produce uranium-232, but this has not yet been observed experimentally.
When uranium isotope is formed from the decay of neptunium-237?
A: uranium-233
Problem: Please answer a question about the following article about Nigeria:
According to a 2001 report from The World Factbook by CIA, about 50% of Nigeria's population is Muslim, 40% are Christians and 10% adhere to local religions. But in some recent report, the Christian population is now sightly larger than the Muslim population. An 18 December 2012 report on religion and public life by the Pew Research Center stated that in 2010, 49.3 percent of Nigeria's population was Christian, 48.8 percent was Muslim, and 1.9 percent were followers of indigenous and other religions, or unaffiliated. Additionally, the 2010s census of Association of Religion Data Archives has reported that 46.5 percent of the total population is Christian, slightly bigger than the Muslim population of 45.5 percent, and that 7.7 percent are members of other religious groups.
In 2001, what percent of Nigeria's population was Christian?
A: 40%
Problem: Please answer a question about the following article about United States Air Force:
The ground-attack aircraft of the USAF are designed to attack targets on the ground and are often deployed as close air support for, and in proximity to, U.S. ground forces. The proximity to friendly forces require precision strikes from these aircraft that are not possible with bomber aircraft listed below. They are typically deployed as close air support to ground forces, their role is tactical rather than strategic, operating at the front of the battle rather than against targets deeper in the enemy's rear.
What type of aircraft is not appropriate to be used in close proximity of US ground troops?
A:
bomber aircraft