| A | B |
|---|
| A microscopic magnetic region composed of a group of atoms whose magnetic fields are aligned in a common direction is called a(n)________. In most materials, when these groups are randomly distributed, the substance will show_____ no magnetism. | domain; no |
| A solenoid is in an upright position on a table. A counterclockwise current of electrons-- when viewed from above--causes the solenoid to have a ______ magnetic pole at its bottom end. If a compass is placed at the top of the solenoid, the north pole of the compass would be_______. | south; repelled |
| A 2.0 m wire segment carrying a current of 0.60 A oriented parallel to a unifrom magnetic field of 0.50 T experiences a force of what magnitude? | 0.0 N |
| A current-carrying wire 0.50 m long is positioned perpendicular to a uniform magnetic field. If the current is 10.0 A and there is a resultant force of 3.0 N on the wire due to the interaction of the current and field, what is the magnetic field of strength? | 0.60 T |
| A bar magnet falls through a loop of wire with a constant velocity, and the north pole enters the loop first. The induced current will be greatest when the magnet is located so that the loop is | near either the north or the south pole |
| According to Lenz’s law, the magnetic field of an induced current in a conductor will | oppose a change in the applied magnetic field |
| According to Lenz’s law, if the applied magnetic field changes, | the induced field attempts to keep the total field strength constant |
| A coil with 150 turns and a cross-sectional area of 1.00 m 2 experiences a magnetic field whose strength increases by +0.65 T in 1.80 s. The plane of the coil is perpendicular to the plane of the applied magnetic field. What is the induced emf in the coil? | -54 V |
| The operation of an electric motor depends on | the magnetic force acting on a current-carrying wire in a magnetic field. |
| Under which condition is the back emf in an electric motor at its maimum value? | Motor speed is at maximum . |
| An electric current that changes directions at regular intervals is called | alternating current |
| Which of the following determines the maximum generated emf in an ac generator? | ALL OF THE ABOVE-a. the coil rotation rate or angular frequency; b. the magnetic field strength, B; c. the loop area, A |
