Unit 5 Electric and Magnetic

 Which statement is true about an electromagnet?

• It is a permanent magnet.
• Increasing the number of coils decreases the strength.
• It cannot be turned off.
• It is made by wrapping current carrying wire around an iron core.

What is a property of matter that causes objects to attract or repel each other?

• compass
• electric charge
• electric circuit
• electric field

Which is a characteristic of most electrical conductors?

• They can be cut easily.
• Negative charges move easily through them.
• Positive charges move easily through them.
• They are soft and and flexible.

 If one burned out bulb causes all of the lights to fail in a circuit, what might you conclude?

• The circuit is a parallel circuit.
• More batteries are needed.
• The circuit is a series circuit.
• They are soft and and flexible.

 If a compass is placed near an electromagnet what would happen if the switch is closed?

• The compass will do nothing.
• The compass needle will turn.
• A spark will jump from the nail.
• The wire will become an insulator.

Clara added another light to an electrical circuit and all the lights became dimmer. What is the most likely cause of the dimmer lights?

• The batteries are weak.
• The light bulbs are hot.
• The circuit is a parallel circuit.
• The circuit is a series circuit.

You are going to build an electromagnet for a lab investigation. Which of the following lab supplies do you need to build an electromagnet?

• insulated wire, compass, iron bar
•  iron bar, battery and holder, light bulb
• compass, iron bar, light bulb
• insulated wire, iron bar, battery and holder

How are a copper wire and aluminum foil alike?

• Negative charges move through them easily,
• They are both silver colored metals.
• They are both used to insulate wires.
• Negative charges can't move through them

Why are parallel circuits more useful in more appliances than series circuits?

• Parallel circuits are cheaper to build.
• They allow many appliances to be used at one time
• Parallel circuits take up less room
• Series circuits produce short circuits, but parallel circuits don't.

How is an electromagnet like a bar magnet?

• They are both made of wire.
• They both need electricity to work
• They both have a N pole and a S pole.
• They are both strong permanent magnets.