Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The black-body problem was revisited in 1905, when Rayleigh and Jeans (on the one hand) and Einstein (on the other hand) independently proved that classical electromagnetism could never account for the observed spectrum. These proofs are commonly known as the "ultraviolet catastrophe", a name coined by Paul Ehrenfest in 1911. They contributed greatly (along with Einstein's work on the photoelectric effect) to convincing physicists that Planck's postulate of quantized energy levels was more than a mere mathematical formalism. The very first Solvay Conference in 1911 was devoted to "the theory of radiation and quanta". Max Planck received the 1918 Nobel Prize in Physics "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta".
Who received the Nobel Prize in Physics based on the destruction of energy quanta?
A: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Bateman was responsible for the building of 36 new buildings for the university both on and off campus, including the expansion of the Harold B. Lee Library. He was also one of several key college leaders who brought about the creation of the Mountain West Conference, which BYU's athletics program joined — BYU previously participated in the Western Athletic Conference. A BYU satellite TV network also opened in 2000 under his leadership. Bateman was also president during the September 11th attacks in 2001. The planes crashed on a Tuesday, hours before the weekly devotional normally held at BYU. Previous plans for the devotional were altered, as Bateman led the student body in a prayer for peace. Bateman was followed by Cecil O. Samuelson in 2003. Samuelson was succeeded by Kevin J Worthen in 2014.
What did BYU's athletic program join under Pres. Bateman?
A: the Mountain West Conference

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
However, according to research firm NPD, sales of devices running Windows in the United States have declined 21 percent compared to the same time period in 2011. As the holiday shopping season wrapped up, Windows 8 sales continued to lag, even as Apple reported brisk sales. The market research firm IDC reported an overall drop in PC sales for the quarter, and said the drop may have been partly due to consumer reluctance to embrace the new features of the OS and poor support from OEM for these features. This capped the first year of declining PC sales to the Asia Pacific region, as consumers bought more mobile devices than Windows PCs.
What is IDC?
A: market research firm

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In the Middle Ages, several powerful Somali empires dominated the regional trade including the Ajuran Sultanate, which excelled in hydraulic engineering and fortress building, the Sultanate of Adal, whose general Ahmad ibn Ibrahim al-Ghazi (Ahmed Gurey) was the first commander to use cannon warfare on the continent during Adal's conquest of the Ethiopian Empire, and the Sultanate of the Geledi, whose military dominance forced governors of the Omani empire north of the city of Lamu to pay tribute to the Somali Sultan Ahmed Yusuf.
What state did Adal conquer?
A:
the Ethiopian Empire