Problem: Planck constant:

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".

When was the first Solvay Conference held?
---
A: 1911

Problem: Nintendo Entertainment System:

In the longer run, however, with the NES near its end of its life many third-party publishers such as Electronic Arts supported upstart competing consoles with less strict licensing terms such as the Sega Genesis and then the PlayStation, which eroded and then took over Nintendo's dominance in the home console market, respectively. Consoles from Nintendo's rivals in the post-SNES era had always enjoyed much stronger third-party support than Nintendo, which relied more heavily on first-party games.

Rivals in what self-identified era enjoyed much stronger 2nd party support?
---
A: unanswerable

Problem: Printed circuit board:

Multi-layer printed circuit boards have trace layers inside the board. This is achieved by laminating a stack of materials in a press by applying pressure and heat for a period of time. This results in an inseparable one piece product. For example, a four-layer PCB can be fabricated by starting from a two-sided copper-clad laminate, etch the circuitry on both sides, then laminate to the top and bottom pre-preg and copper foil. It is then drilled, plated, and etched again to get traces on top and bottom layers.

A silver-clad laminate can be found in what kind of circuit board?
---
A: unanswerable

Problem: Alaska:

According to an October 1998 report by the United States Bureau of Land Management, approximately 65% of Alaska is owned and managed by the U.S. federal government as public lands, including a multitude of national forests, national parks, and national wildlife refuges. Of these, the Bureau of Land Management manages 87 million acres (35 million hectares), or 23.8% of the state. The Arctic National Wildlife Refuge is managed by the United States Fish and Wildlife Service. It is the world's largest wildlife refuge, comprising 16 million acres (6.5 million hectares).

What percentage of Alaska is maintained by the US federal government?
---
A:
65%