Right Hand Rule Magnetism

Determine the direction of the magnetic force acting on the proton or electron in each situation below.

A.

B.

How do magnets work?

Two long straight parallel wires are separated by a distance of 25 cm. One is carrying a current of 2 A, the other 4 A (the currents are aimed in the same direction) . What is the magnetic field, $\vec{B}$ at a point directly in the middle of the wires?

Three long wires parallel to the x axis carry currents as shown below. If I = 20 A, what is the magnetic field at the origin (magnitude and direction) ?