Final answer:
The question asks to calculate a proton's travel distance before it stops when shot from a charged plane. Physics concepts, specifically electric field and work-energy theorem, are used to determine this distance.
Step-by-step explanation:
The question involves calculating how far a proton travels before reaching its turning point when shot from an infinite charged plane with a known surface charge density. To solve this, we must use the concepts of electric fields produced by a charged plane and the work-energy principle in physics. To find the turning point, we equate the initial kinetic energy of the proton to the work done against the electric field created by the surface charge density of the plane.