Question

question 9 (1 point)
a vertical wire carries a current straight down. to the east of this wire, the magnetic field points
north.
east.
south.
down.

Explanation:

To determine the direction of the magnetic field around a current - carrying wire, we use the right - hand rule. For a current - carrying wire, if we grasp the wire with our right hand such that our thumb points in the direction of the current, the fingers of our right hand curl in the direction of the magnetic field lines.

In this problem, the current in the vertical wire is straight down. So, we point our right - hand thumb downward (in the direction of the current). Now, we consider a point to the east of the wire. To find the direction of the magnetic field at this point, we look at the direction in which our fingers curl at that location.

When the thumb is pointing down (current direction), and we consider a point to the east of the wire, the magnetic field lines (direction of the magnetic field) at that point will point south. Let's verify this: the right - hand rule for a current - carrying wire gives a circular magnetic field pattern around the wire. With the current going down, the magnetic field circles the wire in a clockwise direction (when viewed from above the wire). A point to the east of the wire, in a clockwise - circling magnetic field, will have the magnetic field direction pointing south.

Answer:

C. south