Problem: Marvel Comics:

In 1961, writer-editor Stan Lee revolutionized superhero comics by introducing superheroes designed to appeal to more all-ages readers than the predominantly child audiences of the medium. Modern Marvel's first superhero team, the titular stars of The Fantastic Four #1 (Nov. 1961), broke convention with other comic book archetypes of the time by squabbling, holding grudges both deep and petty, and eschewing anonymity or secret identities in favor of celebrity status. Subsequently, Marvel comics developed a reputation for focusing on characterization and adult issues to a greater extent than most superhero comics before them, a quality which the new generation of older readers appreciated. This applied to The Amazing Spider-Man title in particular, which turned out to be Marvel's most successful book. Its young hero suffered from self-doubt and mundane problems like any other teenager, something readers could identify with.

What superhero team used secret identities?
---
A: unanswerable


Problem: Separation of powers under the United States Constitution:

During the Age of Enlightenment, philosophers such as John Locke advocated the principle in their writings, whereas others, such as Thomas Hobbes, strongly opposed it. Montesquieu was one of the foremost supporters of separating the legislature, the executive, and the judiciary. His writings considerably influenced the opinions of the framers of the United States Constitution.

Who was an advocate of separation of powers?
---
A: John Locke


Problem: Light-emitting diode:

With nitrides containing aluminium, most often AlGaN and AlGaInN, even shorter wavelengths are achievable. Ultraviolet LEDs in a range of wavelengths are becoming available on the market. Near-UV emitters at wavelengths around 375–395 nm are already cheap and often encountered, for example, as black light lamp replacements for inspection of anti-counterfeiting UV watermarks in some documents and paper currencies. Shorter-wavelength diodes, while substantially more expensive, are commercially available for wavelengths down to 240 nm. As the photosensitivity of microorganisms approximately matches the absorption spectrum of DNA, with a peak at about 260 nm, UV LED emitting at 250–270 nm are to be expected in prospective disinfection and sterilization devices. Recent research has shown that commercially available UVA LEDs (365 nm) are already effective disinfection and sterilization devices. UV-C wavelengths were obtained in laboratories using aluminium nitride (210 nm), boron nitride (215 nm) and diamond (235 nm).

 What is the range of wavelengths for cheap UV LEEDs?
---
A: unanswerable


Problem: Light-emitting diode:

Machine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more widespread. Barcode scanners are the most common example of machine vision, and many low cost products use red LEDs instead of lasers. Optical computer mice are an example of LEDs in machine vision, as it is used to provide an even light source on the surface for the miniature camera within the mouse. LEDs constitute a nearly ideal light source for machine vision systems for several reasons:

 non-LEDs are often used for what type of systems?
---
A:
unanswerable