The Lorentz force is a force exerted by the electromagnetic field on the charged particle, that is, it is the rate at which linear momentum is transferred from the electromagnetic field to the particle. Associated with it is the power which is the rate at which energy is transferred from the electromagnetic field to the particle. That power is v ⋅ ⋅ F = q v ⋅ ⋅ E . Notice that the magnetic field does not contribute to the power because the magnetic force is always perpendicular to the velocity of the particle.