Exam 22: Electromagnetic Induction

The figure shows a uniform magnetic field that is normal to the plane of the conducting loop of resistance R. Note: the area of the non-circular portion of the circuit is negligible compared to that of the loop. -Suppose that the radius of the loop is 0.500 m. At what rate must B change with time if the emf induced in the loop is $\pi$ volts?

Two coils share a common axis as shown in the figure. The mutual inductance of this pair of coils is 6.0 mH. If the current in coil 1 is changing at the rate of 3.5 A/s, what is the magnitude of the emf generated in coil 2?

A 0.100-m long solenoid has a radius of 0.050 m and 1.50 × 10⁴ turns. The current in the solenoid changes at a rate of 6.0 A/s. A conducting loop of radius 0.0200 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown. -Determine the induced emf in the loop.

A single conducting loop with an area of 2.0 m² rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown. -Determine the strength of the magnetic field in which the loop rotates.

The figure shows a uniform, 3.0-T magnetic field that is normal to the plane of a conducting, circular loop with a resistance of 1.5 $\varOmega$ and a radius of 0.024 m. The magnetic field is directed out of the paper as shown. Note: The area of the non-circular portion of the wire is considered negligible compared to that of the circular loop. -What is the average current around the loop if the magnitude of the magnetic field is doubled in 0.4 s?

The figure shows a uniform, 3.0-T magnetic field that is normal to the plane of a conducting, circular loop with a resistance of 1.5 $\varOmega$ and a radius of 0.024 m. The magnetic field is directed out of the paper as shown. Note: The area of the non-circular portion of the wire is considered negligible compared to that of the circular loop. -What is the magnitude of the average induced emf in the loop if the magnitude of the magnetic field is doubled in 0.4 s?

A 0.60-T magnetic field is directed perpendicular to the plane of a circular loop of radius 0.40 m. What is the magnitude of the magnetic flux through the loop?

The figure shows a uniform magnetic field that is normal to the plane of the conducting loop of resistance R. Note: the area of the non-circular portion of the circuit is negligible compared to that of the loop. -Which entry in the table below correctly pairs the change in the system with the direction of the induced current through R?

A circuit is pulled with a 21-N force toward the right to maintain a constant speed v. At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper. As the circuit moves, a 4.0-A current flows through a 6.0- $\varOmega$ resistor. -What is the magnitude of v?

The figure shows a circular, conducting loop that is connected to a 5.0-V battery and a switch S. Immediately after the switch S is closed, the current through the loop changes at a rate of 15 A/s and the emf induced in the loop has a magnitude of 5.0 V. Determine the self-inductance of the coil.

A 0.100-m long solenoid has a radius of 0.050 m and 1.50 × 10⁴ turns. The current in the solenoid changes at a rate of 6.0 A/s. A conducting loop of radius 0.0200 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown. -Determine the self-induced emf in the solenoid due to the changing current.

A flexible, circular conducting loop of radius 0.15 m and resistance 4.0 $\varOmega$ lies in a uniform magnetic field of 0.25 T. The loop is pulled on opposite sides by equal forces and stretched until its enclosed area is essentially zero m², as suggested in the drawings. It takes 0.30 s to close the loop. -Which one of the following phrases best describes the direction of the induced magnetic field generated by the current induced in the loop while the loop is being stretched?

The figure shows a uniform, 3.0-T magnetic field that is normal to the plane of a conducting, circular loop with a resistance of 1.5 $\varOmega$ and a radius of 0.024 m. The magnetic field is directed out of the paper as shown. Note: The area of the non-circular portion of the wire is considered negligible compared to that of the circular loop. -If the magnetic field is held constant at 3.0 T and the loop is pulled out of the region that contains the field in 0.2 s, at what rate is energy dissipated in R?

A closed loop carries a current that increases with time. Which one of the quantities listed below relates the emf induced in the loop to the rate at which the current is increasing?

A small power plant produces a voltage of 6.0 kV and 150 A. The voltage is stepped up to 240 kV by a transformer before it is transmitted to a substation. The resistance of the transmission line between the power plant and the substation is 75 $\varOmega$ . -What is the current in the transmission line from the plant to the substation?

A conducting bar moves to the left at a constant speed v on two conducting rails joined at the left as shown. As a result of the bar moving through a constant magnetic field, a current I is induced in the indicated direction. Which one of the following directions is that of the magnetic field?

In the drawing, a coil of wire is wrapped around a cylinder from which an iron core extends upward. The ends of the coil are connected to an ac voltage source. After the alternating current is established in the coil, an aluminum ring of resistance R is placed onto the iron core and released. Which one of the following statements concerning this situation is false?

A 0.45-m metal rod moves 0.11 m in a direction that is perpendicular to a 0.80-T magnetic field in an elapsed time of 0.036 s. Assuming that the acceleration of the rod is zero m/s², determine the emf that exists between the ends of the rod.

A 0.100-m long solenoid has a radius of 0.050 m and 1.50 × 10⁴ turns. The current in the solenoid changes at a rate of 6.0 A/s. A conducting loop of radius 0.0200 m is placed at the center of the solenoid with its axis the same as that of the solenoid as shown. -What is the magnetic flux through the small loop when the current through the solenoid is 2.50 A?

Two coils, 1 and 2, with iron cores are positioned as shown in the figure. Coil 1 is part of a circuit with a battery and a switch. -Immediately after the switch S is closed, which one of the following statements is true?