Exam 22: Electromagnetic Induction

A circular copper loop is placed perpendicular to a uniform magnetic field of 0.75 T.Due to external forces, the area of the loop decreases at a rate of 7.26 × 10^-3 m²/s.Determine the induced emf in the loop.

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. -Assume the switch S has been closed for a long time.Which one of the following statements is true?

A long, straight wire is in the same plane as a rectangular, conducting loop.The wire carries a constant current I as shown in the figure.Which one of the following statements is true if the wire is suddenly moved toward the loop?

A circular coil has 275 turns and a radius of 0.045 m.The coil is used as an ac generator by rotating it in a 0.500 T magnetic field, as shown in the figure.At what angular speed should the coil be rotated so that the maximum emf is 175 V?

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 $\Omega$ 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, what is the magnitude of the average induced emf in the loop?

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. -Assume that S has been closed for a long time.Which one of the following statements is true if coil 2 is moved toward C?

A uniform magnetic field passes through two areas, A₁ and A₂.The angles between the magnetic field and the normals of areas A₁ and A₂ are 30.0° and 60.0°, respectively.If the magnetic flux through the two areas is the same, what is the ratio A₁/A₂?

A loop is pulled with a force F to the right to maintain a constant speed of 8.0 m/s.The loop has a length of 0.15 m, a width of 0.080 m, and a resistance of 200.0 $\Omega$ .At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper.The magnitude of the field is 1.2 T. -Determine the magnitude of the force required to pull the loop.

22-3 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. -What is the period of the induced current?

A circular coil of wire has 25 turns and has a radius of 0.075 m.The coil is located in a variable magnetic field whose behavior is shown on the graph.At all times, the magnetic field is directed at an angle of 75° relative to the normal to the plane of a loop.What is the average emf induced in the coil in the time interval from t = 5.00 s to 7.50 s?

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 $\Omega$ . -What percentage of the power produced at the power plant is lost in transmission to the substation?

22-3 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. -With what angular frequency does the loop rotate?

A solenoid with 1000 turns has a cross-sectional area of 7.0 cm² and length of 25 cm.How much energy is stored in the magnetic field of the solenoid when it carries a current of 10.0 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. -Assume that S has been closed for a long time.Which one of the following changes will not result in an induced current in coil 2 that flows from left to right through R.

22-4 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 mutual inductance of this combination.

A loop with a resistance of 4.0 $\Omega$ is pushed to the left at a constant speed of 2.0 m/s by a 24 N force.At the instant shown in the figure, the loop is partially in and partially out of a uniform magnetic field.An induced current flows from left to right through the resistor.The length and width of the loop are 2.0 m and 1.0 m, respectively. -Determine the magnitude of the induced emf in the loop.

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 $\Omega$ 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?

22-3 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.

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 loop is pulled with a force F to the right to maintain a constant speed of 8.0 m/s.The loop has a length of 0.15 m, a width of 0.080 m, and a resistance of 200.0 $\Omega$ .At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper.The magnitude of the field is 1.2 T. -What is the magnitude of the emf induced in the loop?