TASK DEFINITION: This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
PROBLEM: Passage: Infrared reflectography (fr; it; es), as called by art conservators, can be applied to paintings to reveal underlying layers in a completely non-destructive manner, in particular the underdrawing or outline drawn by the artist as a guide. This often reveals the artist's use of carbon black, which shows up well in reflectograms, as long as it has not also been used in the ground underlying the whole painting. Art conservators are looking to see whether the visible layers of paint differ from the underdrawing or layers in between such alterations are called pentimenti when made by the original artist. This is very useful information in deciding whether a painting is the prime version by the original artist or a copy, and whether it has been altered by over-enthusiastic restoration work. In general, the more pentimenti the more likely a painting is to be the prime version. It also gives useful insights into working practices.

SOLUTION: What painting technique is used to reveal working practices?

PROBLEM: Passage: The principles of imperialism are often generalizable to the policies and practices of the British Empire "during the last generation, and proceeds rather by diagnosis than by historical description". British imperialism often used the concept of Terra nullius (Latin expression which stems from Roman law meaning 'empty land'). The country of Australia serves as a case study in relation to British settlement and colonial rule of the continent in the eighteenth century, as it was premised on terra nullius, and its settlers considered it unused by its sparse Aboriginal inhabitants.

SOLUTION: Imperialism is less often associated with which sovereignty?

PROBLEM: Passage: Bohr also introduced the quantity , now known as the reduced Planck constant, as the quantum of angular momentum. At first, Bohr thought that this was the angular momentum of each electron in an atom: this proved incorrect and, despite developments by Sommerfeld and others, an accurate description of the electron angular momentum proved beyond the Bohr model. The correct quantization rules for electrons in which the energy reduces to the Bohr model equation in the case of the hydrogen atom were given by Heisenberg's matrix mechanics in 1925 and the Schrodinger wave equation in 1926: the reduced Planck constant remains the fundamental quantum of angular momentum. In modern terms, if J is the total angular momentum of a system with rotational invariance, and Jz the angular momentum measured along any given direction, these quantities can only take on the values

SOLUTION:
Who reduced the increased Planck constant?