Current loop?

Electricity and Magnetism Level 2

An electric current of 1 Ampere is flowing along a horizontal wire. At x = 0 x=0 the wire splits into a circle of radius 0.05 m and then comes back together at x = 0.1 x=0.1 m. What is the magnitude in Tesla of the magnetic field in the middle of this loop of wire?


The answer is 0.

View wiki
David Mattingly by David Mattingly

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

3 solutions

Discussions for this problem are now closed

Nhat Le
Dec 19, 2013

At the center point, the magnetic field created by the upper half of the loop exactly cancels the magnetic field created by the lower half. The contribution by the straight section of the wire is 0 0 , since the straight wire points directly towards the center point.

Thus, the net magnetic field at the center is 0 0 .

8 Helpful 4 Interesting 2 Brilliant 3 Confused

Oho! I thought the circle is formed as a coil.

Leonardo DiCaprio - 7 years, 5 months ago

Please give a figure in these kind of Questions. The language lead me to visualize something else entirely and it cost me the correct answer . Thanks !

Abhishek Mangal - 7 years, 4 months ago

Can you post a rough sketch of how the situation looks like? I can't really visualize it.

Parth Thakkar - 7 years, 4 months ago
Tim Henke
Dec 19, 2013

In both parts of the wire, the current is flowing in the same direction. Note that it does not behave like a coil, but rather two seperate wires. Both wires generate a rotating magnetic field around themselves. Both magnetic fields rotate in the same direction, because the current flows in the same direction in both. Because the middle is on the left of one of the rotating fields and on the right on the other and both rotate in the same direction, the flows cancel out. So the answer is 0 \boxed{0}

5 Helpful 0 Interesting 0 Brilliant 2 Confused
Arghyanil Dey
Apr 13, 2014

At the point of splitting the current splits into two same part. So net field at the centre of the loop is 0 for two circular parts & the point lies along the horizontal line so that the straight wire can't produce any magnetic feild at the centre of the loop.

2 Helpful 0 Interesting 0 Brilliant 1 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...