Electromagnet Quiz

Lucia puts an electromagnet in a track. The electromagnet is turned off. It can slide back and forth in the track. Then, Lucia puts a permanent magnet beside the right end of the track. When the electromagnet is turned on, it slides across the track toward the permanent magnet. What can Lucia do to make the electromagnet slide faster?

• use fewer loops of wire in the electromagnet to make it smaller

• add a magnet to the left side of the track to repel the electromagnet

• make the permanent magnet smaller so that it has a weaker pull

• leave the electromagnet off so that it does not attract the permanent magnet

Electromagnets are different than permanent metal magnets because they need an electric current to make them work. How are electromagnets the same as permanent magnets?

• They both use a coil of wire.

• They can both only be made of plastic.

• They can both be turned off.

• They both have a north and south pole.

The strength of an electromagnet depends on _______.

• the number of coils of wire

• the diameter (width) of the iron core

• the number of batteries

• all of these

Alisha made the electromagnet shown below. She used the electromagnet to pick up some paper clips. Alisha wants the electromagnet to be able to pick up even more paper clips. What should she change?

• She should use bigger paper clips.

• She should move the battery to the other side of the nail.

• She should add more loops of wire around the nail.

• She should move the nail farther from the paper clips.

The telegraph was one of the first machines that could send a message almost instantly to someone hundreds of miles away. The telegraph used a current to turn an electromagnet on and off. When the electromagnet was on it was attracted to a metal plate and it would tap. A series of taps was used to send a message. How can a current in a wire be used to make an electromagnet?

• add a stronger battery to the wire

• wrap the wire around a piece of iron

• hold a magnet just touching the wire

• wrap the wire around a magnet

Two kinds of magnets are shown below. Which of the following best describes a difference between the two magnets?

• Magnet 2 can attract or repel objects, but magnet 1 can only attract objects.

• Magnet 2 creates a continuous magnetic field, but magnet 1 only creates a temporary magnetic field.

• Magnet 2 can attract more kinds of material than magnet 1 can attract.

• Magnet 2 can be switched on and off more easily than magnet 1.

Jeanna went to a store that sold little glass animals. Near the cash register was a floating glass swan. There was a small black disc attached to the bottom of the swan. The box it floated over was plugged in. Jeanna carefully studied the box and swan. She made three correct conclusions about its design: The force of [dropdown] was making the swan float. [dropdown] was attached to the bottom of the swan. The box under the swan [dropdown]

The bell shown in the picture works the same way that a doorbell works. The bell only rings when the electromagnet pushes on the beater bar. The magnetic force moves the beater bar so that it rings the bell. Most of the time, the bell does not ring because the electromagnet is off. What turns the electromagnet on when a person pushes the doorbell button?

• the energy of the person's finger

• the movement of another magnet

• a build up of static charge

• a current in the coil of the electromagnet

Two kinds of magnets are shown below. Jackson wants to hang a small piece of paper on the metal door of his refrigerator. Which type of magnet would be best for Jackson to use, and why?

• Magnet 2 would work best because it would attract the refrigerator with more force.

• Magnet 1 would work best because it has a continuous magnetic field.

• Magnet 1 would work best because it would attract the refrigerator with more force.

• Magnet 2 would work best because it has a continuous magnetic field.

Gina's class makes a circuit using a battery, a wire, and an iron core. Gina's teacher places a magnet next to the iron core of the circuit and the magnet begins to move without anyone touching it. Why does the magnet move?

• The iron core uses the heat being transferred from the battery to make magnetic energy.

• The electricity running through the circuit causes the iron core to have magnetic properties.

• The battery that is connected to the circuit is a magnet that transfers energy to the iron core.

• The magnetic energy running through the circuit causes the iron core to give off electricity.