Solution

ID: past-exam-of-the-short-options-paper-shared-by-prelims-and-parts-a-and-b-of-the-physics-course-of-the-university-of-oxford/2018/s7/1/b/solution

With zero scalar potential, the nonrelativistic charged-particle Lagrangian in SI units is kinetic energy plus . Thus
The velocity-dependent magnetic term changes canonical momentum but does not contribute to the mechanical energy.

New to topics? Read the docs here!