TASK DEFINITION: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
PROBLEM: Who found that physical action cannot take on an arbitrary value?, Context: Classical statistical mechanics requires the existence of h (but does not define its value). Eventually, following upon Planck's discovery, it was recognized that physical action cannot take on an arbitrary value. Instead, it must be some multiple of a very small quantity, the "quantum of action", now called the Planck constant. Classical physics cannot explain this fact. In many cases, such as for monochromatic light or for atoms, this quantum of action also implies that only certain energy levels are allowed, and values in between are forbidden.

SOLUTION: Planck

PROBLEM: An object that is fixed in place and cannot move is said to be also what?, Context: The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface.

SOLUTION: immobile

PROBLEM: What does Thapar decry as helping to put too much focus on certain aspects of Indian history?, Context: Romila Thapar notes that the division into Hindu-Muslim-British periods of Indian history gives too much weight to "ruling dynasties and foreign invasions", neglecting the social-economic history which often showed a strong continuity. The division into Ancient-Medieval-Modern periods overlooks the fact that the Muslim conquests occurred gradually during which time many things came and went off, while the south was never completely conquered. According to Thapar, a periodisation could also be based on "significant social and economic changes", which are not strictly related to a change of ruling powers.[note 1]

SOLUTION:
division into Hindu-Muslim-British periods