A moving charge in a magnetic field feels the Lorentz force F = q v x B, perpendicular to both velocity and field, which bends the path into a curve without changing the speed. This force ledger is exact only for stated charge, mass, speed, and field under a uniform-field assumption. Real plasmas add field gradients, collisions, pitch-angle spread, relativistic corrections, and measurement uncertainty.
The Lorentz-force magnitude is checked before the path is drawn. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Magnetic force uses charge, speed, and field
Charge 2 coulombs, speed 3 meters per second, and field 4 tesla give force 24 newtons.
qvB=2⋅3⋅4=24N
The force changes direction, not speed
The checked force is perpendicular to the velocity arrow, so this model bends the path into gyromotion.