One of the major advantages of using electromagnets is that they can be turned on and off. An ordinary magnet cannot be turned off and on; the only way to decrease the effect of an ordinary magnet would be to remove it, shield it (cover it up or put it in a box) or destroy it. Being able to turn an electromagnet on and off is useful. For example, think of a junk yard where a large electromagnet is used to pick up old cars and move them to a new location. After it has picked the car up and moved it, the operator can just turn off the magnet and the car is released. In a doorbell, (illustration at the left) you hold the doorbell button and current will flow through the electromagnet. But when you release the button, the current will stop flowing through the electromagnet and the magnetic field will collapse.
Other advantages of an electromagnet include being able to easily increase or decrease the strength of the magnetic field by increasing the current in the electromagnet, or by changing the number of coils. An electromagnet can be made much stronger - with a much stronger pull - than an ordinary magnet. In addition, the polarity - the north-south ends - of an electromagnet can be reversed by changing the direction of the current flowing in the wire. This reverses the direction of the magnetic field.
Advantage of Electromagnets
What are two advantages of electromagnets?
Answers will vary, but may include:
1. The ability to turn the magnet on and off.
2. The ability to strengthen the magnet.
