Question

The Lorentz force is

• A. on the charge rest in magnetic fied with v
• B. on the charge moving in magnetic field with v
• C. None of above
• D. on the charge rest in electric field

Answer 1

Answer: (B)

on the charge moving in magnetic field with v

Answer 2

The Lorentz force is the total electromagnetic force on a charged particle, given by $\vec{F} = q(\vec{E} + \vec{v} \times \vec{B})$. The magnetic component of this force, $\vec{F}_B = q(\vec{v} \times \vec{B})$, acts only on a charge that is moving in a magnetic field. The option "on the charge moving in magnetic field with v" correctly describes the condition for this magnetic force component, which is the defining and unique aspect of the Lorentz force in the presence of a magnetic field.