Today I left for you problems to work on in my absence. We'll talk about these over the next few days.
0 Comments
We practiced a bit with flux, changes in flux, induced magnetic fields, and the induced currents that produce these induced magnetic fields. It can be a lot to keep track of. We also saw effects produced by electrons swirling in copper when a strong magnet moves over the copper. Assignment:
Bring your textbook tomorrow. We will work on some problems. Lenz's Rule was a central feature of our work today. This rule is a quick way to determine the direction of flow of a current induced by a change in magnetic flux. What Lenz's Rule tells us is that the magnetic field of the induced current will oppose the CHANGE in magnetic flux through a circuit.
Faraday's Law On Friday we dealt with Faraday's Law, named for Michael Faraday, one of the most productive physicists ever. Though he was not trained mathematically, his persistence and intuition led him to many breakthoughs, including how to make electricity by using magnetic fields. You saw things similar to what he saw on Thursday when you moving the two coils (one of which carried current) with respect to each other. The needle of the meter connected to the coil that had no current moved back and forth, indicating an electric current had been 'induced' in it. Magnetic Flux through a copper loop
The blue arrows above represent a magnetic field in which the loop is immersed. The red arrow is called the "area vector", A, which is the mathematical representation of the area inside the copper loop. The bigger the area, the longer the vector. And the vector is normal to the plane of the loop; that's how we indicate the orientation of the loop. Does that make sense to you? So the flux of the magnetic field through the loop is defined by the following 'dot product': |
Archives |