A long wire lies in a tangle on the surface of a table,as shown below.When a current is run through the wire as shown,the largest component of the magnetic field at X points
A)into the table.
B)out of the table.
C)parallel to the nearest segment of wire.
D)antiparallel to the nearest segment of wire.
E)along a circle which has its center at the center of the overall loop.

Question

A long wire lies in a tangle on the surface of a table,as shown below.When a current is run through the wire as shown,the largest component of the magnetic field at X points 
A)into the table. 
B)out of the table. 
C)parallel to the nearest segment of wire. 
D)antiparallel to the nearest segment of wire. 
E)along a circle which has its center at the center of the overall loop.

Quizplus · Accepted Answer

According to the right-hand rule, the magnetic field created by a current-carrying wire forms circles around the wire. At point X, the magnetic field due to each segment of wire near it will have a component perpendicular to the surface of the table, pointing outwards for the upper segments and inwards for the lower segments. The net effect of all these fields will be a magnetic field pointing out of the table, perpendicular to the surface at X. Therefore, the correct choice is B, out of the table.

A Long Wire Lies in a Tangle on the Surface