Chapter 4: Q8DQ (page 911)
How might a loop of wire carrying a current be used as a compass? Could such a compass distinguish between north and south? Why or why not?
We would have to know the direction of the current in the loop in order to determine where is north and where is south.
Over 30 million students worldwide already upgrade their learning with Vaia!
All the tools & learning materials you need for study success - in one app.
Get started for free
The text states that good thermal conductors are also good electrical conductors. If so, why don’t the cords used to connect toasters, irons, and similar heat-producing appliances get hot by conduction of heat from the heating element?
Two coils are wound around the same cylindrical form. When the current in the first coil is decreasing at a rate of , the induced emf in the second coil has magnitude . (a) What is the mutual inductance of the pair of coils? (b) If the second coil has 25 turns, what is the flux through each turn when the current in the first coil equals ? (c) If the current in the second coil increases at a rate of , what is the magnitude of the induced emf in the first coil?
In the circuit of Fig. E25.30, the 5.0 Ω resistor is removed and replaced by a resistor of unknown resistance R. When this is done, an ideal voltmeter connected across the points band creads 1.9 V. Find (a) the current in the circuit and (b) the resistance R. (c) Graph the potential rises and drops in this circuit (see Fig. 25.20).
An 18-gauge copper wire (diameter 1.02 mm) carries a current
with a current density of . The density of free electrons for
copper iselectrons per cubic meter. Calculate (a) the current in
the wire and (b) the drift velocity of electrons in the wire.
An electrical conductor designed to carry large currents has a circular cross section 2.50 mm in diameter and is 14.0 m long. The resistance between its ends is . (a) What is the resistivity of the material? (b) If the electric-field magnitude in the conductor is 1.28 V/m, what is the total current? (c) If the material has free electrons per cubic meter, find the average drift speed under the conditions of part (b).
What do you think about this solution?
We value your feedback to improve our textbook solutions.
