Question

At any point the magnetic field lines are in the direction of:

A) the magnetic force on a moving positive charge
B) the magnetic force on a moving negative charge
C) the velocity of a moving positive charge
D) the velocity of a moving negative charge
E) none of the above

Answer 1

The magnetic field lines are in the direction of the magnetic force on a moving positive charge, based on the right hand rule 1.

Step-by-step explanation:

At any point, the magnetic field lines are in the direction of the magnetic force on a moving positive charge (answer A). According to the right hand rule (RHR-1), when determining the direction of the magnetic force on a positive charge, you point your thumb in the direction of the velocity vector (v), and your fingers in the direction of the magnetic field (B). The force (F) is then directed perpendicularly to the palm. This means the force on a positive charge is directed outwards from the palm. However, for a negative charge, the force is in the opposite direction to that on a positive charge. Therefore, given that magnetic field lines represent the direction of the magnetic force on a moving positive charge, it can be concluded that option A is the correct answer.