Final answer:
To determine the magnetic force on a negatively charged object moving through a magnetic field, use the right-hand rule. Point your fingers in the direction of the magnetic field, sweep them in the direction of the object's velocity, and your thumb will indicate the direction of the magnetic force.
Step-by-step explanation:
To determine the magnetic force on a negatively charged object moving through a magnetic field, you can use the right-hand rule. First, use your right hand and point your fingers in the direction of the magnetic field. Then, sweep your fingers in the direction of the object's velocity. Your thumb will point in the direction of the magnetic force. However, if the charge is negative, you need to reverse the direction found by these steps.