Question: Assistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to the very high bandwidth fiber links that form the Internet backbone. For some time, computers were commonly equipped with IrDA interfaces, which allowed them to send and receive data to nearby machines via infrared.
Is there an answer to this question: Where are infrared LEDs used in everday life?

Answer: theaters


Question: Other sources include fortified food and dietary supplements, which come in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. This review cited studies which found low plasma zinc concentrations after zinc oxide and zinc carbonate were consumed compared with those seen after consumption of zinc acetate and sulfate salts. However, harmful excessive supplementation is a problem among the relatively affluent, and should probably not exceed 20 mg/day in healthy people, although the U.S. National Research Council set a Tolerable Upper Intake of 40 mg/day.
Is there an answer to this question: Why is zinc carbonate perfectly absorbed in the body?

Answer: unanswerable


Question: Heat is energy in transit that flows due to temperature difference. Unlike heat transmitted by thermal conduction or thermal convection, thermal radiation can propagate through a vacuum. Thermal radiation is characterized by a particular spectrum of many wavelengths that is associated with emission from an object, due to the vibration of its molecules at a given temperature. Thermal radiation can be emitted from objects at any wavelength, and at very high temperatures such radiations are associated with spectra far above the infrared, extending into visible, ultraviolet, and even X-ray regions (i.e., the solar corona). Thus, the popular association of infrared radiation with thermal radiation is only a coincidence based on typical (comparatively low) temperatures often found near the surface of planet Earth.
Is there an answer to this question: How is heat associated with emission from an object?

Answer: unanswerable


Question: The Hanoverian king George II of Great Britain was passionately devoted to his family’s continental holdings, but his commitments in Germany were counterbalanced by the demands of the British colonies overseas. If war against France for colonial expansion was to be resumed, then Hanover had to be secured against Franco-Prussian attack. France was very much interested in colonial expansion and was willing to exploit the vulnerability of Hanover in war against Great Britain, but it had no desire to divert forces to central Europe for Prussia's interest.
Is there an answer to this question: What was Britain's obligation to Hanover if colonial expansion via war with France was to be resumed?

Answer:
Hanover had to be secured against Franco-Prussian attack