The definition of resistivity (rho=E/J) implies that an electric field exists inside a conductor. Yet we saw in Chapter 21 that there can be no electrostatic electric field inside a conductor. Is there a contradiction here?


Batteries are always labeled with their emf; for instance, an AA flashlight batter is labeled "1.5 volts." Would it also be appropriate to put a label on batteries stating how much current they provide?


Why does an electric light bulb nearly always burn out just as you turn on the light, and almost never while the light is shining?


Eight flashlight batteries in series have an emf of about 12 V, similar to that of a car battery. Could they be used to start a car with a dead battery?