A New Look at Electric Potential Induced electric fields are produced not by static charges but by a changing magnetic flux. Although electric fields produced in either way exert forces on charged particles. there is an important difference between them. The simplest evidence of this difference is that the field lines of induced electric fields form closed loops. […]
Energy Stored in a Magnetic Field When we pull two particles with opposite signs of charge away from each other, we say that the resulting electric potential energy is stored in the electric field of the particles. We get it back from the field by letting the particles move closer together again. In the same way we can […]
RL Circuits In Section 28-8 we saw that if we suddenly introduce an emf’l!; into a single-loop circuit containing a resistor R and a capacitor C, the charge on the capacitor does not build up immediately to its final equilibrium value C’l!; but approaches it in an exponential fashion: The rate at which the charge builds […]
Self Induction If two coils-which we can now call inductors-are near each other. a current i in one coil produces a magnetic flux cf>B through the second coil. We have seen that if we change this flux by changing the current, an induced emf appears in the second coil according to Faraday’s law. An induced emf appears in […]
Inductance of a Solenoid Consider a long solenoid of cross-sectional area A. What is the inductance per unit length near its middle? To use the defining equation for inductance (Eq. 31-30), we must calculate the flux linkage setup by a given current in the solenoid windings. Consider […]
Inductors and Inductance We found in Chapter 26 that a capacitor can be used to produce a desired electric field. We considered the parallel-plate arrangement as a basic type of capacitor. Similarly, an inductor (symbol J.2QQ,) can be used to produce a desired magnetic field. We shall consider a long solenoid (more specifically, a short length near […]
A New Look at Electric Potential Induced electric fields are produced not by static charges but by a changing magnetic flux. Although electric fields produced in either way exert forces on charged particles. there is an important difference between them. The simplest evidence of this difference is that the field lines of induced electric fields form […]
A Reformulation Of Faraday’s Law Consider a particle of charge qo moving around the circular path of The work W done on it in one revolution by the induced electric field is where is the induced emf-that is, the work done per unit charge in moving the test charge around the path. From another point of […]
Induced Electric Fields Let us place a copper ring of radius r in a uniform external magnetic field, as in . The field-neglecting fringing-fills a cylindrical volume of radius R. Suppose that we increase the strength of this field at a steady rate, perhaps by increasing – in an appropriate way – the current I the windings […]
Eddy Currents Suppose we replace the conducting loop of with a solid conducting plate. If we then move the plate out of the magnetic field ‘as we did the loop the relative motion of the field and the conductor again induces a current in the conductor. Thus, we again encounter an opposing force and must do […]