Question

A vertical wire carries a current straight down. To the east of this wire, the magnetic field points:
a) Eastwards
b) Downwards
c) Southwards
d) Northwards

Answer 1

Hint: We can determine the magnetic field produced by moving charges using a right-hand rule—the magnetic field produced by a current in wire spirals around the wire in a ring. We can obtain it by facing our right thumb in the current direction in the wire and turning our fingers. Our fingers will be turned in the same direction as the magnetic field around a wire.

Complete answer:
There is an easy method of finding the connection between the direction of the current running in a conductor and the movement of the magnetic field around the same conductor. The technique is called the Right-Hand Rule. Stated, the Right-Hand Rule states that the magnetic field lines provided by a current-carrying wire will be shown in the same direction as the folded fingers of a person's right hand, with the thumb facing in the direction of the current flow.
The magnetic field formed by an electric current is continuously oriented perpendicular to the current flow direction. The magnetic field around a wire seems like when the wire has a current flowing in it. We use it to indicate a magnetic field and arrows on lines of the field to show the magnetic field. When there is no current, then no magnetic field will be there.
The circles are field lines, and they also have a direction shown by the arrows on the lines. Like the situation with electric field lines, the greater the number of lines in an area, the stronger the magnetic field.
Use the right-hand rule. Lead our thumb down. Our fingers bend toward the south when we look on the wire's east side. The direction of field lines is known by using the right-hand thumb rule.

Option (c) is correct.

Note:
An electric current cross through a straight wire. When the thumb is faced in the direction of conventional current, the curled fingers will then show in the direction of the magnetic flux lines around the conductor—the direction of the magnetic field results from this convention.