13. What property of electromagnets is NOT a property of permanent magnets: 2. Electromagnets contain iron.
b. Electromagnets can be turned on and off.
c. Electromagnets attract iron or materials that contain iron.
d. Electromagnets have a north pole that points to the north.
14. How do electromagnets differ from regular magnets?
a. They can be turned on and off
b. Their polarity can be reversed
c. Their strength can be changed
d. All the above
15. Which of the following could be used as the core of a simple electromagnet?
a. pencil
b. iron nail
c. aluminum foil
d. drinking straw
16. To change the polarity of an electromagnet, you would:
a. Reverse the current's direction
b. Reverse the direction in which the coil is wound
c. Remove the iron core from within the coil of wire
d. Turn the battery, or other power source, upside-down.
I need help on all questions