QUES: In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, Mataré produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had already invented the transistor before them, the company rushed to get its "transistron" into production for amplified use in France's telephone network.

In what year was the point-contact transistor invented?
What is the answer?
ANS: 1948
QUES: The use of drones by the Central Intelligence Agency in Pakistan to carry out operations associated with the Global War on Terror sparks debate over sovereignty and the laws of war. The U.S. Government uses the CIA rather than the U.S. Air Force for strikes in Pakistan in order to avoid breaching sovereignty through military invasion. The United States was criticized by[according to whom?] a report on drone warfare and aerial sovereignty for abusing the term 'Global War on Terror' to carry out military operations through government agencies without formally declaring war.

Why did the US use the CIA instead of the Air Force to run drones?
What is the answer?
ANS: to avoid breaching sovereignty through military invasion
QUES: Zinc chemistry is similar to the chemistry of the late first-row transition metals nickel and copper, though it has a filled d-shell, so its compounds are diamagnetic and mostly colorless. The ionic radii of zinc and magnesium happen to be nearly identical. Because of this some of their salts have the same crystal structure and in circumstances where ionic radius is a determining factor zinc and magnesium chemistries have much in common. Otherwise there is little similarity. Zinc tends to form bonds with a greater degree of covalency and it forms much more stable complexes with N- and S- donors. Complexes of zinc are mostly 4- or 6- coordinate although 5-coordinate complexes are known.

What is the determining factor where zinc and magnesium are very similar chemically?
What is the answer?
ANS:
ionic radius