The assumption that black-body radiation is thermal leads to an accurate prediction: the total amount of emitted energy goes up with the temperature according to a definite rule, the StefanBoltzmann law (187984). But it was also known that the colour of the light given off by a hot object changes with the temperature, so that "white hot" is hotter than "red hot". Nevertheless, Wilhelm Wien discovered the mathematical relationship between the peaks of the curves at different temperatures, by using the principle of adiabatic invariance. At each different temperature, the curve is moved over by Wien's displacement law (1893). Wien also proposed an approximation for the spectrum of the object, which was correct at high frequencies (short wavelength) but not at low frequencies (long wavelength). It still was not clear why the spectrum of a hot object had the form that it has (see diagram).
What assumption that black-body radiation is what leads to an accurate prediction?
thermal

Islanders speak both English and a creole language known as Norfuk, a blend of 18th-century English and Tahitian. The Norfuk language is decreasing in popularity as more tourists travel to the island and more young people leave for work and study reasons; however, there are efforts to keep it alive via dictionaries and the renaming of some tourist attractions to their Norfuk equivalents. In 2004 an act of the Norfolk Island Assembly made it a co-official language of the island. The act is long-titled: "An Act to recognise the Norfolk Island Language (Norf'k) as an official language of Norfolk Island." The "language known as 'Norf'k'" is described as the language "that is spoken by descendants of the first free settlers of Norfolk Island who were descendants of the settlers of Pitcairn Island". The act recognises and protects use of the language but does not require it; in official use, it must be accompanied by an accurate translation into English. 32% of the total population reported speaking a language other than English in the 2011 census, and just under three-quarters of the ordinarily resident population could speak Norfuk.
What part of the residents of Norfolk Island could speak Norfuk as of 2011?
under three-quarters

By March 2011, the market share of OS X in North America had increased to slightly over 14%. Whether the size of the Mac's market share and installed base is relevant, and to whom, is a hotly debated issue. Industry pundits have often called attention to the Mac's relatively small market share to predict Apple's impending doom, particularly in the early and mid-1990s when the company's future seemed bleakest. Others argue that market share is the wrong way to judge the Mac's success. Apple has positioned the Mac as a higher-end personal computer, and so it may be misleading to compare it to a budget PC. Because the overall market for personal computers has grown rapidly, the Mac's increasing sales numbers are effectively swamped by the industry's expanding sales volume as a whole. Apple's small market share, then, gives the impression that fewer people are using Macs than did ten years ago, when exactly the opposite is true. Soaring sales of the iPhone and iPad mean that the portion of Apple's profits represented by the Macintosh has declined in 2010, dropping to 24% from 46% two years earlier. Others try to de-emphasize market share, citing that it is rarely brought up in other industries. Regardless of the Mac's market share, Apple has remained profitable since Steve Jobs' return and the company's subsequent reorganization. Notably, a report published in the first quarter of 2008 found that Apple had a 14% market share in the personal computer market in the US, including 66% of all computers over $1,000. Market research indicates that Apple draws its customer base from a higher-income demographic than the mainstream personal computer market.
Apple has remained profitable since what time?
Steve Jobs' return