Question: The quality of a vacuum is indicated by the amount of matter remaining in the system, so that a high quality vacuum is one with very little matter left in it. Vacuum is primarily measured by its absolute pressure, but a complete characterization requires further parameters, such as temperature and chemical composition. One of the most important parameters is the mean free path (MFP) of residual gases, which indicates the average distance that molecules will travel between collisions with each other. As the gas density decreases, the MFP increases, and when the MFP is longer than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. The MFP of air at atmospheric pressure is very short, 70 nm, but at 100 mPa (~6997100000000000000♠️1103 Torr) the MFP of room temperature air is roughly 100 mm, which is on the order of everyday objects such as vacuum tubes. The Crookes radiometer turns when the MFP is larger than the size of the vanes.
Is there an answer to this question: What is particle gas dynamics?

Answer: study of fluid flows

Question: The convergence of these various sources into a uniform theory of groups started with Camille Jordan's Traite des substitutions et des equations algebriques (1870). Walther von Dyck (1882) introduced the idea of specifying a group by means of generators and relations, and was also the first to give an axiomatic definition of an "abstract group", in the terminology of the time. As of the 20th century, groups gained wide recognition by the pioneering work of Ferdinand Georg Frobenius and William Burnside, who worked on representation theory of finite groups, Richard Brauer's modular representation theory and Issai Schur's papers. The theory of Lie groups, and more generally locally compact groups was studied by Hermann Weyl, Elie Cartan and many others. Its algebraic counterpart, the theory of algebraic groups, was first shaped by Claude Chevalley (from the late 1930s) and later by the work of Armand Borel and Jacques Tits.
Is there an answer to this question: What did Walter von Dyck publish in 1870?

Answer: unanswerable

Question: International observers of Council of Europe and US Department of State have questioned the fairness of Armenia's parliamentary and presidential elections and constitutional referendum since 1995, citing polling deficiencies, lack of cooperation by the Electoral Commission, and poor maintenance of electoral lists and polling places. Freedom House categorized Armenia in its 2008 report as a "Semi-consolidated Authoritarian Regime" (along with Moldova, Kosovo, Kyrgyzstan, and Russia) and ranked Armenia 20th among 29 nations in transition, with a Democracy Score of 5.21 out of 7 (7 represents the lowest democratic progress).
Is there an answer to this question: What is the lowest score on the Democracy Score scale?

Answer: 7

Question: Current Governor of the Reserve Bank of India Raghuram Rajan had predicted the crisis in 2005 when he became chief economist at the International Monetary Fund.In 2005, at a celebration honouring Alan Greenspan, who was about to retire as chairman of the US Federal Reserve, Rajan delivered a controversial paper that was critical of the financial sector. In that paper, "Has Financial Development Made the World Riskier?", Rajan "argued that disaster might loom." Rajan argued that financial sector managers were encouraged to "take risks that generate severe adverse consequences with small probability but, in return, offer generous compensation the rest of the time. These risks are known as tail risks. But perhaps the most important concern is whether banks will be able to provide liquidity to financial markets so that if the tail risk does materialise, financial positions can be unwound and losses allocated so that the consequences to the real economy are minimised."
Is there an answer to this question: Who was the current Governor of the Reserve Bank of India that predicted the crisis in 2005?

Answer:
Raghuram Rajan