Context and question: The design of the Institute's Mycenean lions medal and the motto 'Usui civium, decori urbium' has been attributed to Thomas Leverton Donaldson, who had been honorary secretary until 1839. The RIBA Guide to its Archive and History (Angela Mace,1986) records that the first official version of this badge was used as a bookplate for the Institute's library and publications from 1835 to 1891, when it was redesigned by J.H.Metcalfe. It was again redesigned in 1931 by Eric Gill and in 1960 by Joan Hassall. The description in the 1837 by-laws was: "gules, two lions rampant guardant or, supporting a column marked with lines chevron, proper, all standing on a base of the same; a garter surrounding the whole with the inscription Institute of British Architects, anno salutis MDCCCXXXIV; above a mural crown proper, and beneath the motto Usui civium decori urbium ".
When did Joan Hassall acquire the Royal Institute's medal?
Answer: unanswerable
Context and question: The core technology used in a videoconferencing system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labeled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP). The use of audio modems in the transmission line allow for the use of POTS, or the Plain Old Telephone System, in some low-speed applications, such as videotelephony, because they convert the digital pulses to/from analog waves in the audio spectrum range.
How high can audio modems go?
Answer: unanswerable
Context and question: Uranium-238 is the most stable isotope of uranium, with a half-life of about 4.468109 years, roughly the age of the Earth. Uranium-235 has a half-life of about 7.13108 years, and uranium-234 has a half-life of about 2.48105 years. For natural uranium, about 49% of its alpha rays are emitted by each of 238U atom, and also 49% by 234U (since the latter is formed from the former) and about 2.0% of them by the 235U. When the Earth was young, probably about one-fifth of its uranium was uranium-235, but the percentage of 234U was probably much lower than this.
What percentage of the gamma rays of natural uranium are emitted by 234U?
Answer:
unanswerable