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- 1. Multiple-choice1 minute1 ptThe magnetic field of an electromagnet can be increased bychanging the direction of the current.decreasing the current.increasing the number of coils.decreasing the number of coils.
- 2. Multiple-choice1 minute1 ptWhat does this illustration represent?magnetic material that is not magnetizedmagnetic material that is magnetizednon-magnetic materialarrangements of atoms in a domain
- 3. Multiple-choice1 minute1 ptIn this illustration, the magnetic field is strongest ___.near either polenear the north polenear the south polehalfway between the poles
- 4. Multiple-choice1 minute1 ptWhat effect does increasing the current flowing in the wire have on an electromagnet?It decreases the strength of the magnetic field.It increases the strength of the magnetic field.It has no effect on the electromagnet.It causes it to become a permanent magnet.
- 5. Multiple-choice1 minute1 ptYou observe that magnets A and B are attracted to each other and "stick." Which sentence BEST explains this observation?Both are positively charged.Both are tightly bonded to each other.Both are composed of smaller, individual magnets.Both have all their magnetic domains aligned in the same direction.
- 6. Multiple-choice1 minute1 ptAs electrons flow through the metal wire in the center of this motor, the metal begins to turn. This is becauseelectric charges act as tiny magnets.a flow of electrons experiences a force in a magnetic field.positive electric charges are attracted to the south pole of a magnet.positive electric charges are attracted to the north pole of a magnet.
- 7. Multiple-choice1 minute1 ptObjects that keep their magnetic properties for a long time are called ___.electromagnetsmagnetic domainspermanent magnetstemporary magnets
- 8. Multiple-choice1 minute1 ptA coil of wire with a current is called a(n)insulator.solenoid.electromagnet.galvanometer.
- 9. Multiple-choice1 minute1 ptThe function of an electric motor is to change ___.chemical energy to electrical energyelectrical energy to chemical energyelectrical energy to mechanical energymechanical energy to electrical energy
- 10. Multiple-choice1 minute1 ptA coil of wire that has a soft iron core and that acts as a magnet when an electric current is in the coil called a(n)ferromagnet.electromagnet.permanent magnet.temporary magnet.
- 11. Multiple-choice2 minutes1 ptThe primary coil of of a step-up transformer has ten turns and its secondary coil has 100 turns. What is the voltage in the secondary coil if the input voltage in the primary coil is 50 V?5,500 V5,000 V500 V150 V
- 12. Multiple-choice1 minute1 ptWhich of the following best describes how electricity is generated for homes?The spinning of a windmill's blades creates electric current without a generator.Nuclear reactions cause electric current to flow around the reaction chamber.Steam pushes turbine blades in a generator, which changes the mechanical energy into an electric current.Water released from a dam generates electric current, which is transformed into mechanical energy.
- 13. Multiple-choice1 minute1 ptWhen a wire with a current is placed in a magnetic field,electrical energy is transformed into mechanical energy.mechanical energy is transformed into electrical energy.the wire becomes a permanent magnet.the current stops.
- 14. Multiple-choice1 minute1 ptThe process of generating an electric current from the motion of a conductor in a magnetic field isconduction.induction.motion.magnetism.
- 15. Multiple-choice1 minute1 ptElectric current from a generating plant isdirect current transmitted at high voltages, but usually used at low voltages.alternating current transmitted at high voltages, but usually used at low voltages.alternating current transmitted at low voltages, but usually used at high voltages.direct current transmitted at low voltages, but usually used at high voltages.
- 16. Multiple-choice1 minute1 ptIn an electric motor, a commutatoris made out of dozens of wire loops wrapped around a ferromagnetic core.repeatedly reverses the flow of current through the armature.is a magnet.is directly connected to the current source.
- 17. Multiple-choice1 minute1 ptWhich of the following is a form of electromagnetic induction?changing electrical energy to mechanical energy that produces soundproducing mechanical energy by sending electric current through an electromagnetusing an electromagnet to measure electric currentproducing electric current by moving a magnet through a wire loop
- 18. Multiple-choice2 minutes1 ptThe primary coil (plug end) has twenty turns and the secondary coil (light) has two turns. What is the voltage at the lamp?15 V120 V12 V1,200 V
- 19. Multiple-choice2 minutes1 ptThe primary coil (plug end) has twenty turns and the secondary coil (light) has two turns. What is the current at the lamp?12 A15 A96 A1.5 A
- 20. Multiple-choice1 minute1 ptElectric current should pass through a ___ after being transmitted by a power plant and before it enters your home.step-up transformergeneratorturbinestep-down transformer
