Practice for Unit 4 electricity and mag.

Like poles of a magnet do what?

• repel
• attract 
• nothing 

What is a wire in a circuit wrapped around an iron core called?

• electromagnet
• generator
• electric motor

What is a complete path through which electric charges can flow called?

• magnetic pole
• electric circuit 
• electric resistance
• magnetic field 

What is the force of attraction or repulsion of magnetic materials?

• electricity
• magnetism 
• energy
• electromagnetism 

What is the region of force around a magnet known as?

• magnetic field
• magnetic pole
• magnetic domain 
• lodestone

A balloon is rubbed all over with wool.  The balloon will now attract wool because the balloon and wool

• are magnets
• have opposite charges
• have like charges
• have neutral charges

Which of the following could be used as the core of a simple electromagnet?

• drinking straw
• iron nail 
• a soda bottle
• an ink pen

What is voltage?

• a measure of electric current
• a kind of static elecricity
• a kind of current electricity
• a measure of potential energy difference

What is the purpose of an iron core in an electromagnet?

• to hold the loops of wire in place
• to make the magnetic force stronger
• to change the direction of the electric current
• to change the direction of the magnetic force

A scientist observed that the needle of a compass moved when it was placed near a wire carrying an electric current.  What did this observation show?

• Opposite charges attract.
• Electric current generates a magnetic field.
• Magnetized wires generate electricity.
• Like charges repel.