Your friend insists that a strong magnetic field is required to induce a current in a coil that

step 1 In this question, we have three goals. First, we want to come up with an experiment to prove tha

Your friend insists that a strong magnetic field is required...

Key Concepts

Electromagnetic Induction

Electromagnetic induction is the principle by which a varying magnetic field generates an electric current in a conductor. This concept underlies the operation of generators and many other electrical devices, emphasizing that it is the change in the magnetic field rather than the magnitude of a static field that induces current.

Faraday's Law of Induction

Faraday's Law states that the induced electromotive force in a circuit is proportional to the rate of change in magnetic flux through the circuit. This law is central to understanding why a moving magnet relative to a coil or a changing magnetic environment results in current production, whereas a constant magnetic field, no matter how strong, does not.

Magnetic Flux Change

Magnetic flux is the measure of the total magnetic field passing through a given area. The key aspect in electromagnetic induction is not the strength of the magnetic field alone, but the presence of a change in the magnetic flux over time. A dynamic change, such as through movement or altering orientation, is essential to generate an induced current.

Relative Motion Between Magnet and Conductor

The relative motion between a magnetic field source, like a magnet, and a conductor, such as a coil, is crucial for inducing current. This movement causes a temporal change in the magnetic flux experienced by the conductor, making the dynamic interaction more important than simply having a strong magnetic field in a stationary setup.

Transcript

00:01 In this question, we have three goals.

00:04 First, we want to come up with an experiment to prove that your friend is correct, that a strong magnetic field will indeed help induce a current in a coil that has no battery.

00:15 Now, the second and the third goal is to come up with an experiment where no current is induced even with a strong magnetic field to prove that your friend is not completely correct.

00:26 So let's start with the first experiment.

00:29 To show this experiment, i will set up a coil of wire that looks like this, and i will also set a permanent magnet right next to it with the north pole this way and the south pole this way.

00:45 Now, whenever you have a permanent magnet, you will have magnetic field coming out of the north pole and circling back to the south pole, making a loop.

00:54 But in this case, to save space, i'm just going to draw the magnetic field coming out of the north pole.

01:00 And notice that the magnetic field will go through this coil of wire.

01:07 And i know that i didn't draw them completely symmetrical, but it should be symmetrical.

01:14 So in this case, my experiment is that i will now move the coil of wire closer to the permanent magnet.

01:27 So before i move this coil of wire, i observe, so before moving, coil, i observe that no current is induced.

01:44 But as i move the coil closer to the permanent magnet, i noticed that there is indeed an induced current.

01:55 So why would this experiment help prove that your friend is correct? well, as you move coil closer to permanent magnet, the coil experiences a stronger b field.

02:27 And you notice that there is indeed induced current.

02:32 So this experiment seems to suggest and conclude that when you are experiencing a stronger magnetic field, you will somehow have induced current.

02:45 So this is your goal number one, to prove that your friend is correct.

02:49 But you notice that after you set up two, similar experiments, your friend's conclusion is not completely correct.

02:57 So let's look at the second setup.

02:59 What if in this case i have the same coil of wire next to a strong permanent magnet and another setup complete the same.

03:19 The only difference between the two is that in this second setup, your permanent magnet is weaker.

03:29 Okay.

03:31 So you have the same.

03:32 Set up with one strong magnet and one weak magnet...