is a theory describes a gas as a large number of small particles (atoms or molecules), all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container.

Answer is =  Kinetic Molecular Theory of Gases

Explanation:

Kinetic Molecular Theory says that " The particles of gas are in constant motion and have perfectly elastic collisions. The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.