Exam 20: Electromagnetic Induction

A series LR circuit includes a 9.00 V battery, a resistance of 0.500 Ω, and an inductance of 0.800 H. What is the greatest energy stored by the inductor after the switch is closed?

Eddy currents in conductors

A 0.40 H inductor has a current that rises from zero to 3.0 A in 6.0 s. What is the average power required to accomplish this?

Reducing the magnetic field to 71% of its previous value changes the magnetic energy density in the field to ________% of its original value.

A series LR circuit includes a 9.0 V battery, a resistance of 0.50 Ω, and an inductance of 0.80 H. What is the induced emf 2.0 s after the switch has been closed?

A metal rod of length L moves with velocity v, perpendicular to its length, in a magnetic field B, which is perpendicular to both the rod and its velocity. If the length of the rod is doubled, what happens to the electric field in the rod?

A series LR circuit consists of a battery, resistor, inductor and a switch. When the switch is closed the circuit has a time constant of 8.0 s. If the resistance and inductance of the circuit are both doubled, what is the resulting time constant?

A generator is designed to produce a maximum emf of 170 V while rotating at 3200 rpm. The coils of the generator are circular with diameter 7.50 cm. Assuming the magnetic field in the generator is 0.0750 T, what is the number of loops needed in the generator coil?

Electric fields that arise from changing magnetic fields have all the properties below except

The current in a 0.40 H inductor increases form 2.0 A to 3.0 A in 1.5 s. The energy stored by the inductor during this process increases by

A loop of wire is moved through a region of uniform magnetic field. As it is moved, its orientation with respect to the magnetic field direction does not change. The induced current in the loop

A conducting rod is free to slide horizontally on frictionless rails separated by 2.0 m. At a particular time, the rod is sliding at 3.0 m/s to the right, as shown. There is a uniform magnetic field of magnitude 0.66 mT directed into the page. If the resistance R is 220 mΩ, what is the current in the circuit at this time?

For the typical household electricity in the United States and Canada, what is the amplitude of the provided emf?

What number of turns on the secondary is needed to reduce the voltage from 120 V to 9.0 V if there are 40 turns on the primary of a step-down transformer?

The emf produced by an ac generator is given by ε = ωNBA sin ωt. In SI units, what is the value of ω for a frequency of 60.0 Hz?

A dc motor is connected to an emf of 12.0 V. The resistance of its windings is 2.0 Ω. At normal operating speed, the motor delivers 6.0 W of mechanical power. What current does it draw at normal operating speed?

A circular coil lays flat on a horizontal table in a region where the magnetic field is straight down. The magnetic field is suddenly removed. When viewed from above, what is the direction of the current in the coil as the field is removed?

Lenz's law arises because of the following basic principle

What is the inductance of a coil that has an emf of 0.82 V induced in it while the current through it is changing at a rate of 2.0 A/s?

The principle of operation that transformers depend upon is the induction of current in the secondary windings due to