IN: Is it true that does total internal reflection occur at the critical angle?

Total internal reflection is the phenomenon which occurs when a propagated wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. If the refractive index is lower on the other side of the boundary and the incident angle is greater than the critical angle, the wave cannot pass through and is entirely reflected. The critical angle is the angle of incidence above which the total internal reflection occurs. This is particularly common as an optical phenomenon, where light waves are involved, but it occurs with many types of waves, such as electromagnetic waves in general or sound waves. When a wave reaches a boundary between different materials with different refractive indices, the wave will in general be partially refracted at the boundary surface, and partially reflected. However, if the angle of incidence is greater (i.e. the direction of propagation is closer to being parallel to the boundary) than the critical angle -- the angle of incidence at which light is refracted such that it travels along the boundary -- then the wave will not cross the boundary, but will instead be totally reflected back internally. This can only occur when the wave in a medium with a higher refractive index (n) reaches a boundary with a medium of lower refractive index (n). For example, it will occur with light reaching air from glass, but not when reaching glass from air.

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OUT: no

IN: Is it true that can a sub come back in in soccer?

In association football, a substitute is a player who is brought on to the pitch during a match in exchange for an existing player. Substitutions are generally made to replace a player who has become tired or injured, or who is performing poorly, or for tactical reasons (such as bringing a striker on in place of a defender). Unlike some sports (such as American football, ice hockey or Kabaddi), a player who has been substituted during a match may take no further part in it.

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OUT: no

IN: Is it true that is moscow the largest city in the world?

Moscow is a major political, economic, cultural, and scientific centre of Russia and Eastern Europe, as well as the largest city entirely on the European continent. By broader definitions Moscow is among the world's largest cities, being the 14th largest metro area, the 18th largest agglomeration, the 15th largest urban area, and the 11th largest by population within city limits worldwide. According to Forbes 2013, Moscow has been ranked as the ninth most expensive city in the world by Mercer and has one of the world's largest urban economies, being ranked as an alpha global city according to the Globalization and World Cities Research Network, and is also one of the fastest growing tourist destinations in the world according to the MasterCard Global Destination Cities Index.

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OUT: no

IN: Is it true that is a vp an officer of a company?

A vice president (in British English: vice-president for governments and director for businesses) is an officer in government or business who is below a president (managing director) in rank. It can also refer to executive vice presidents, signifying that the vice president is on the executive branch of the government, university or company. The name comes from the Latin vice meaning ''in place of''. In some countries, the vice president is called the deputy president. In everyday speech, the abbreviation VP can be used.

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OUT:
yes