Force on a Wire

Magnetic Simulation I

Description:

These simulation shows a wire and the sum of the wire's magnetic field and an external magnetic field. In some cases the external field is supplied by a second wire. The force on the wire is shown by a black arrow and the magnitude of the force is shown in yellow at the bottom of the simulation when you hold the mouse button down on the wire. You can move the wire by dragging it. The current may flow either into the screen (away from you) or out of the screen (towards you).

The magnetic field vectors are shown in color with blue indicating a weaker field and black indicating a stronger field.

Question 25:

Click on the button to set up the simulation. For this question there is a field in the top half of the simulation only. Drag the wire around into various parts of the simulation.

Why is there no force on the wire in the bottom half of the simulation?
What direction does the external magnetic field in the top half of the simulation point?
What direction does the current flow in the wire?
What is the direction and magnitude of the force on the wire in the top half of the simulation?

Question 26:

Click on the button to set up the simulation. Drag the wire around into various parts of the simulation.

What direction does the external magnetic field point?
What direction does the current flow in the wire?
How does the magnitude of the force change as you move the wire from left to right?
How does the direction of the force change as you move the wire from left to right?
The magnetic field in the top half of the simulation for question 25 was a uniform field. How is the external field in this question different from that of question 25?

Question 27:

Click on the button to set up the simulation. In this simulation there are two wires. The green wire does not move. Drag the black wire around into various parts of the simulation.

What direction does the current flow in the black wire?
What direction does the current flow in the green wire?
What direction does the force on the black wire point relative to the green wire?
How does the magnitude of the force on the black wire change as you move away from the green wire?
What direction does the force on the green wire point relative to the black wire?

Question 28:

Click on the button to set up the simulation. In this simulation there is an external magnetic field in the right half of the simulation only. Drag the wire around into various parts of the simulation.

What force acts on the wire in the left half of the simulation?
What direction does the external magnetic field in the right half of the simulation point?
What direction does the current flow in the wire?
What is the direction of the force on the wire in the right half of the simulation?

Questions 29 & 30:

Click on each of the buttons to set up the simulation and answer the following questions about both cases. In these two simulation both wires can be moved.

What direction does the current flow in the black wire?
What direction does the current flow in the green wire?
What direction does the force on the black wire point, relative to the green wire?
What direction does the force on the green wire point, relative to the black wire?