Exam 30: Induction and Inductance

As a loop of wire with a resistance of 10 $\Omega$ moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5 mJ/s. The induced current in the loop:

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries a constant current i, as shown. While the wire is being moved toward the rectangle the current in the rectangle is:

A copper penny slides on a horizontal frictionless table. There is a square region of constant uniform magnetic field perpendicular to the table, as shown. Which graph correctly shows the speed v of the penny as a function of time t?

As an externally generated magnetic field through a certain conducting loop increases in magnitude, the field produced at points inside the loop by the current induced in the loop must be:

An inductor with inductance L restistor with resistance R are wired in series to an ideal battery with emf $\varepsilon$ . A switch in the circuit is closed at time 0, at which time the current is zero. A long time after the switch is thrown the potential differences across the inductor and resistor:

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries an increasing current in the direction shown. The current in the rectangle is:

A 6.0 mH inductor is in a series circuit with a resistor and an ideal battery. At the instant the current in the circuit is 5.0 A the energy stored in the inductor is:

In the circuit shown, there will be a non-zero reading in galvanometer G:

A 10-turn ideal solenoid has an inductance of 4.0 mH. To generate an emf of 2.0 V the current should change at a rate of:

A long narrow solenoid has length and a total of N turns, each of which has cross-sectional area A. Its inductance is:

An 8.0-mH inductor and a 2.0-(\Omega\) resistor are wired in series to an ideal battery. A switch in the circuit is closed at time 0, at which time the current is 0. The current reaches half its final value at a time of:

In each of the following operations, energy is expended. The LEAST percentage of returnable electrical energy will be yielded by:

A rod lies across frictionless rails in a uniform magnetic field B, as shown. The rod moves to the right with speed v. In order for the emf around the circuit to be zero, the magnitude of the magnetic field should:

A square loop of wire moves with a constant speed v from a field-free region into a region of uniform B field, as shown. Which of the five graphs correctly shows the induced current i in the loop as a function of time t?

One hundred turns of insulated copper wire are wrapped around an iron core of cross-sectional area 0.100 m². The circuit is completed by connecting the coil to a 10- $\Omega$ resistor. As the magnetic field along the coil axis changes from 1.00 T in one direction to 1.00 T in the other direction, the total charge that flows through the resistor is:

A car travels northward at 75 km/h along a straight road in a region where Earth's magnetic field has a vertical component of 0.50 *10^-4 T. The emf induced between the left and right side, separated by 1.7 m, is:

At any instant of time the total magnetic flux through a stationary conducting loop is less in magnitude than the flux associated with an externally applied field. This might occur because:

The four wire loops shown have edge lengths of either L, 2L, or 3L. They will move with the same speed into a region of uniform magnetic field directed out of the page. Rank them according to the maximum magnitude of the induced emf, least to greatest.

A 3.5 mH inductor and a 4.5 mH inductor are connected in parallel. The equivalent inductance is:

In the experiment shown: