Magnet - right hand rule - direction of compass North

In summary, a loop of wire with a clockwise current running through it is placed on top of a cardboard. When viewed from above, the loop runs from left to right. Placing a compass beneath the cardboard, the N pole of the compass will point towards the top of the monitor. This can be determined using the right hand rule, with the thumb pointing to the right and the fingers wrapping around the wire.
  • #1
dandy9
28
0

Homework Statement


A length of wire extends upward through a piece of cardboard, bends around, forming a loop, and extends back down through the cardboard. All that is visible above the surface of the cardboard is this loop of wire. From your perspective, you are looking downward on the piece of cardboard so the loop runs from your left to your right. The loop of wire has a current running through it in a clockwise direction (from left to right above the cardboard). If a compass is placed on the cardboard beneath the loop, in which direction will the N pole of the compass point?

a) It will point toward the right of the monitor.
b) It will point toward the left of the monitor.
c) It will point toward the bottom of the monitor.
d) It will point toward the top of the monitor.


Homework Equations


Right hand rule.


The Attempt at a Solution


I did the right hand rule and pointed my thumb to the right. My fingers were then pointing "out" of the screen. So the answer is either "toward the top of the monitor" or "toward the bottom of the monitor". I think it's toward the bottom, but I'm not sure and can't risk getting this question wrong. Can anyone help me?
Thanks!
 
Physics news on Phys.org
  • #2
I see others are avoiding this question and it is about to slip off the first page. No wonder; it is quite unclear! Do we have a loop of wire lying in the plane of the cardboard so the "monitor" looking down sees a circle of wire? Or is it a loop standing up perpendicular to the cardboard so the observer sees a line of wire going left to right; likely the loop is completed right to left underneath the cardboard in this scenario. In the first case, the magnetic field would be up toward the monitor or down away from it (depending on whether the current is conventional positive current or electron flow), so none of the choices are correct. Must be the second case! Picture your thumb (left or right hand depending on the type of current) going to the right, fingers wrapped around the wire. For positive current, the fingers go away from you (toward the top of the monitor) under the wire, and toward you above the wire. That should give you the answer, using your class convention for positive/negative current flow.
 

1. What is the right hand rule for determining the direction of a compass North?

The right hand rule is a technique used to determine the direction of a magnetic field. It states that if you point your right thumb in the direction of the current flow and curl your fingers around the wire, your fingers will curl in the direction of the magnetic field.

2. How does the right hand rule apply to a compass?

The right hand rule can be applied to a compass by envisioning the needle of the compass as a current-carrying wire. If you point your thumb in the direction of the needle's movement, your fingers will curl in the direction of the magnetic field, indicating the direction of North.

3. Does the right hand rule work for all types of magnets?

Yes, the right hand rule can be applied to all types of magnets, including permanent magnets and electromagnets. It is a fundamental principle of electromagnetism that applies to all magnetic fields.

4. Can the right hand rule be used to determine the direction of a magnetic field in 3D space?

Yes, the right hand rule can be used to determine the direction of a magnetic field in 3D space. By extending your thumb, index finger, and middle finger perpendicular to each other, you can determine the direction of the magnetic field along the three axes.

5. How is the right hand rule related to the Earth's magnetic field?

The Earth's magnetic field is similar to that of a bar magnet, with the North magnetic pole located near the geographic South Pole. The direction of the Earth's magnetic field is determined using the right hand rule, with the magnetic North pole pointing towards the Earth's geographic North Pole.

Similar threads

  • Introductory Physics Homework Help
Replies
11
Views
458
  • Introductory Physics Homework Help
Replies
31
Views
549
  • Introductory Physics Homework Help
Replies
16
Views
381
  • Introductory Physics Homework Help
Replies
1
Views
178
  • Introductory Physics Homework Help
Replies
4
Views
266
  • Introductory Physics Homework Help
Replies
10
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
281
  • Introductory Physics Homework Help
Replies
12
Views
538
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
191
Back
Top