| 11. | The concept of a test particle often simplifies problems, and can provide a good approximation for physical phenomena.
|
| 12. | Thus, when a test particle is forced to approach the electron, it causes changes that can be measured.
|
| 13. | Notably, in order to deflect a test particle from its geodesic path, an external force must be applied.
|
| 14. | The most common version of GEM is valid only far from isolated sources, and for slowly moving test particles.
|
| 15. | Analogously, the world lines of test particles in free fall are spacetime geodesics, the straightest possible lines in spacetime.
|
| 16. | Where such objects are concerned, the laws governing the behavior of test particles are sufficient to describe what happens.
|
| 17. | The equations for the motion of test particles in the Kerr spacetime may be obtained using proper Hamilton-Jacobi equations.
|
| 18. | To go with the section on test particles above, here are the equations for the fields in which they move.
|
| 19. | The area enclosed by the test particles does not change and there is no motion along the direction of propagation.
|
| 20. | In simulations with electromagnetic fields the most important characteristics of a "'test particle "'is its electric charge and its mass.
|
