Science worksheet studyguide

which of these is the best definition of electromagnetism?

• The use of electrical energy to create magnets

• The use of magnets to generate an electrical current

• The interaction between electric and magnetic forces

• The appearence of nature in objects that have both electric and magnetic fields.

An electromagnet is made by wrapping many 

turns of wire around an iron bar and causing a current to flow through the wire. How would increasing the electrical current affect the electromagnet?

• It would make the poles of the 

  magnet weaker.

• It would make the poles of the 

  magnet stronger.

• It would decrease the flow of electricity in 

  the iron bar.

• It would increase the flow of electricity in 

  the iron bar.

Which of these correctly describes 

electric current?

• the amount of electric charge on an object 

• the rate at which electric charges pass a given point

• the buildup of electric charge on the surface of an object

• the amount of energy it takes to move a 

  unit of electric charge between two points

 Which statement describes how 

electromagnetism can be used to generate electricity in a power plant?

• Moving a magnet in a coil of wire produces 

  visible light.

• Magnets convert electric energy into 

  mechanical energy.

• Magnets detect the presence of electric 

  currents in nature.

• Moving a magnet in a coil of wire 

  generates an electric current.

Two parallel wires have electrical current 

running through them in opposite directions. Which statement describes the force between the two wires?

• There are no electric or magnetic forces on 

  the wires.

• There is a magnetic force pulling the wires 

  toward one another.

• There is an electric force pulling the wires 

  toward one another.

• There is a magnetic force pushing the wires away from one another.

Olga wants to test if the battery shown in the diagram still produces an electric current. She wraps a wire around a compass and connects each end to the battery as shown in the diagram.

She claims that this device has properties similar to an electromagnet. Which of these statements best defends this claim?

• When electric charges flow through the wire, the voltage of the battery increases.

• When electric charges flow through the wire, the compass becomes demagnetized.

• When electric charges flow through the wire, the compass becomes electrically charged.

• When electric charges flow through the wire, they produce a magnetic field through the coil of wire.

Juan wants to make a motor using simple materials. He wraps copper wire around a small piece of cork 

and uses a pin to secure the cork to an axle balanced between two bar magnets, as shown in the diagram. Two brushes made of springy copper wire just touch two metal pins in the cork that are used to hold the ends of the copper wire in place.

When he connects the copper wire to the batteries, he expects to see the cork spin. Why does Juan expect to see the cork spin?

• The magnetic field produced by the current flow in the coil of wire changes the poles of the 

  bar magnets.

• Electric charges produced by the current flow are pushed into the bar magnets, causing the cork to 

  move in the opposite direction.

• The cork moves so the electric field produced by the current flow in the coil of wire aligns with the 

  magnetic field of the bar magnets.

• The cork moves so the magnetic field produced by the current flow in the coil of wire aligns with the 

  magnetic field of the bar magnets.

 A small bar magnet is shown. A compass is 

placed beside the magnet so that the center of the compass is next to the center of the magnet. Which of these is true? 

• The north pole of the compass needle points at the magnet's south pole.

• The south pole of the compass needle 

  points at the magnet's north pole.

• The north pole of the compass points in the same direction as the magnet's south pole

• The north pole of the compass needle 

  points in the same direction as the magnet's north pole.

Two aluminum balls are 5 cm apart. One is 

negatively charged, and the other is positively charged. A small magnet is placed between the two balls but is not touching either of them. The aluminum balls remain stationary. Which statement describes the electric and magnetic fields?

• There is a magnetic field due to the magnet and no electric field,

• There is a magnetic field between the two 

  balls and no electric field, 

• There is an electric field between the two 

  balls and no magnetic field.

• There is an electric field between the two balls and a magnetic field due to the magnet.

The diagram shows the magnetic field 

surrounding a magnet. 

Where is the magnetic force the strongest?

• position A

• position B

• position C

• position D