Questions: Electromagnets

Question 1

What happens to an electromagnet when you turn off the electricity?

• A. It stays magnetic forever
• B. It loses its magnetism
• C. It becomes stronger
• D. It explodes

Answer: (B)

An electromagnet's magnetism depends on flowing electricity. When the current stops, the magnetic field disappears and the nail is no longer a magnet.

Question 2

Wrapping more coils of wire around the nail makes the electromagnet stronger.

• T. True
• F. False

Answer: True

Each coil of wire adds to the magnetic field. More coils means a stronger concentrated field, which makes the electromagnet more powerful.

Question 3

Name one advantage an electromagnet has over a permanent magnet.

Model answer: An electromagnet can be turned on and off (also acceptable: its strength can be adjusted).

Unlike a permanent magnet, an electromagnet only works when electricity flows. This lets you control when it is magnetic and how strong it is.