Physical Science B Final Exam Review

In audio speakers, an electromagnet is placed in a magnetic field created by a permanent magnet. The ________ in the solenoid rapidly switches direction, which also switches the electromagnet’s _____________.

• Current, magnetic poles

• Current, vibrations

• Poles, circuit

• Poles, magnetic poles

To make the armature in an electric motor spin continuously, the ______ of the current must be ______ after each half-rotation.

• Direction, stopped

• Direction, reversed

• Resistance, reduced

• Resistance, reversed

The picture shows a coiled wire that carries an electrical current. What do the gray lines (NOT the black coil) represent?

• The electric field

• Thermal energy

• The magnetic field

• Light energy

What must be done to use this device for electromagnetic induction?

• Move the wire up and down

• Attached the disconnected end of the wire to close the circuit

• Coil the wire around a screw

• Remove the wire from between the magnets

The diagram below shows electromagnetic induction. The solid black line represents a wire. What do the arrows indicated by part A represent?

• Solenoid

• Current

• Electricity

• Magnetic field

A _________ is a current-carrying wire with many loops. If a metal bar is placed within the coils of a solenoid, then the metal bar becomes a ___________.

• Electromagnet, magnet

• Solenoid, magnet

• Solenoid, current

• Electromagnet, current

If the bar magnet below is cut in half, which answer choice shows the pieces after the magnet has been cut?

• 
• 
• 
• 

How are the magnetic field lines near the south pole of a magnet affected when a second south pole is brought near it?

• The field lines bend toward the second south pole

• The field lines bend away from the second south pole

• The field lines combine with the lines around the second south pole

• The field lines overlap with the lines from the second south pole

What is the function of a switch?

• source of electrical energy

• device that needs electrical energy to operate

• something that conducts

• manages the flow of current in an electric circuit

What is the name and function of this symbol?

• Battery, provides electrical energy

• Switch, controls electric current

• Switch, measures electric current

• Resistor, controls electric current