Welcome to Faraday’s Electromagnetic Lab! To begin, search
“Electromagnetic Lab” in Google, and click on the first link.
Then click “Run Now!” or “Download” to open the simulation.
Once you are in the simulation, click on the “Pickup Coil” tab
above. You should see the screen shown to the right.
Take a minute to familiarize yourself with the controls and parts
of the simulation, and then begin the following activity.
1) By manipulating (moving, altering, etc) the loop of wire or the magnet, come up with six different ways
that an electric current can be induced in the coil. List them below. See Mr. B for a hint if you’re stuck!
2) In general, what must be happening for there to be a current induced in the wire? Be specific!
Some thought and discussion is required for this one!
3) Explain how your answer for question 2 is consistent with each of the six ways that you induced a
current in the loop of wire.
When a current is induced in a loop of wire, there is also an induced
magnetic field associated with this induced current. This second field
is not shown in the simulation. In order to quickly and easily determine
the direction of the induced magnetic field, you can use RHR #3!
RHR #3
If you wrap your fingers around along the way that the induced current flows, your
thumb will point in the direction of the induced magnetic field inside the loop!
thumb shows direction
of Binduced within loop!
Example
fingers wrap like Iinduced
Evilness Warning!
In the simulation, the blue circles represent electrons.
The direction of the induced current is opposite to the way that the electrons flow!
Take a few minutes to practice RHR #3 below. The induced current is shown in the first three
(although the reason for the induced current is not shown in the first three).
Show the direction of the induced magnetic field within each loop of wire.
1)
2)
3)
4) Show Iinduced and Binduced
5) Show Iinduced and Binduced
6) Show Iinduced and Binduced
Now...to decode Lenz’s Law!!!
By moving the North/South end of the magnet in/out of the loop of wire in the simulation and recording
your observations below, you will be able to determine the relationship between the change in magnetic
flux through the loop, and the induced magnetic field in the loop. Whoa.
Trial #1: Moving the North end of the magnet toward the loop of wire.
Draw the bar magnet’s magnetic
field and velocity vector
In which direction is the magnetic flux through the loop?
Show which way the induced current flows
in the loop (remember the evilness warning...)
Trial #2: Moving the North end of the magnet away from the loop of wire.
Draw the bar magnet’s magnetic
field and velocity vector
In which direction is the magnetic flux through the loop?
Show which way the induced current flows
in the loop (remember the evilness warning...)
Trial #3: Moving the South end of the magnet toward the loop of wire.
Draw the bar magnet’s magnetic
field and velocity vector
In which direction is the magnetic flux through the loop?
Show which way the induced current flows
in the loop (remember the evilness warning...)
Trial #4: Moving the South end of the magnet away from the loop of wire.
Draw the bar magnet’s magnetic
field and velocity vector
In which direction is the magnetic flux through the loop?
Show which way the induced current flows
in the loop (remember the evilness warning...)
Grand Finale!
By taking a step back and looking at the four scenarios that you just analyzed, determine the pattern between
the change in the magnetic flux through the loop and the direction of the induced magnetic field in the loop.
This will require some thought/discussion. Bonus if you make the discovery! (Check with Mr. B!)
What is the relationship between the change in the magnetic flux and the induced magnetic field?
Congratulations! You have successfully discovered Lenz’s Law! You rock!