Question

4.2.4 quiz: electromagnetism
question 5 of 10
which action is the best way to turn an electromagnet on and off?
a. slide the magnetic core in and out of the wire coil.
b. add a switch to the electrical circuit.
c. change the shape of the wire coil.
d. increase or decrease the temperature.

Explanation:

An electromagnet works when electric current flows through a wire coil. A switch in the electrical circuit can easily control the flow of current. When the switch is closed, current flows and the electromagnet is on; when the switch is open, current stops and the electromagnet is off. Sliding the magnetic core (A) affects magnetic strength but is not the standard on - off method. Changing the coil shape (C) affects magnetic properties like field distribution, not on/off. Temperature change (D) is not a practical or common way to control an electromagnet's on/off state.

Answer:

B. Add a switch to the electrical circuit.