Assessment-Electromagnets (Other Teachers)

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Online Assessment
Instructions
1) Type in your first and last name in the “Name” box in the top-left corner.
2) Next type in your teacher’s name in the “ID” box.
3) Then type in your school’s full name in the “Email” box.
4) Select the best answer for each question.
5) When you are finished click the “Grade and Submit” button.
6) The grade will be emailed to your teacher.

NOTE: If your teacher’s last name is Elliott, then you are doing the wrong assessment.
---This assessment is only for students of other teachers.
---If your teacher is Mr. Elliott, then please go back to the website and click on the first assessment link instead. Thanks!

Diagram A	Diagram B

Device 01	Device 02

(Two-Part Question)
(1) Identify each device shown in the two diagrams above.
(2) What is wrong with the device in diagram A?

a.	(1) Diagram B is an electromagnet, and Diagram A is an electric motor. (2) In Diagram B the handle is not being turned fast enough to power the light bulb..
b.	(1) The two diagrams are both showing electromagnets being used to make electricity (2) Device 01 will not function properly because the wires are not connected to the battery
c.	(1) Diagram A is a permanent magnet, and Diagram B is an electromagnet. (2) There is nothing wrong with device 01.
d.	(1) Diagram A is an incomplete electromagnet, and Diagram B is a rotational generator. (2) The wires are not connected to the battery with device 01, so there is no magnetic field.

Simple Electromagnet

A student makes an electromagnet and finds that it is only strong enough to pick up one paper clip.
What modification will she need to do in order to make it pick up three paper clips?

a.	use staples instead of paper clips	c.	replace the battery with a bar magnet
b.	use paper clips made of aluminum	d.	wrap more coils around the nail

Diagram 01	Diagram 02
Electromagnet	Electromagnetic Induction (Generator)

Diagram 01:
Key components of an electromagnet: a source of electricity, a coil of wire, and an iron core
Diagram 02:
Key components of a generator: a coil of wire, a permanent magnet, an electrical load

Contrast the two devices displayed above in diagrams 01 and 02.

a.	An electromagnet can not be turned off and on. A generator can be turned off and on.
b.	An electromagnet’s magnetic field will not move the needle on a compass A generator’s magnetic field will move the needle on a compass
c.	With a battery, an iron core, and a coil of wire, you create an electromagnet. Generators induce electrical current via movement between a magnet and a solenoid.
d.	A generator contains a battery, a coil of wire, and an iron nail. An electromagnet contains only a bar magnet and a coil of wire.

Diagram A

A student made an electromagnet by wrapping copper wire around an iron nail (see diagram above). The student then connected each end of the electromagnet to the opposite terminals of a battery.
The electromagnet will best function as a magnet as long as...?

a.	the nail is made of plastic, glass, or rubber
b.	electrical energy is transformed into mechanical energy.
c.	electric current flows through the wire.
d.	electrical energy is transformed into potential energy.

A portion of an electromagnet is shown in the diagram below.

The electromagnet will be completed by adding...?

a.	metal clips.	c.	a battery.
b.	a switch.	d.	insulated wires.

Diagram of a Simple Electromagnet

The diagram above shows a simple electromagnet that can lift seven paper clips
How could you modify this electromagnet so that it would only be able to pick up two paper clips?

a.	Reduce the number of wire wraps in the solenoid around the iron core.
b.	Use a thicker wire with the same number of wraps around the nail.
c.	Move the iron core (the nail) back and forth through the solenoid
d.	Increase the number of wire wraps in the solenoid around the iron core.

Figure A

This figure displays an electromagnet that you could build at home from items from a hardware store.
What are the three key components of an electromagnet?

a.	battery, paper clips, iron nail	c.	coil of wire, solenoid, source of electricity
b.	bar magnet, galvanometer, iron core	d.	solenoid, iron core, source of electricity

Magnetic Resonance Imaging
(MRI)

MRI machines use magnetic fields from powerful electromagnets to create images of the inside of a persons body (see diagram above).
How are the electromagnets in a MRI machine similar to all other electromagnets?

a.	They have coils of wire wrapped around iron cores connected to electrical current.
b.	They rotate permanent magnets through a solenoid to generate electricity.
c.	The consist of capacitors, electrical switches, transformers, and circuit breakers.
d.	The include hundreds of permanent magnets that can not be turned off or on.

Electromagnet Crane

Many scrap yards use electromagnet cranes to sort and move ferrous metal items.
How are the electromagnets in cranes such as this similar to all other electromagnets?

a.	They have electricity flowing through coiled wires wrapped around iron cores.
b.	These electromagnets can not be turned on and off. They are permanent magnets
c.	The strength of the magnetic field cannot be adjusted by the crane operator.
d.	They have aluminum cores surrounded by titanium wires connected to electrical current

10.

Permanent Magnet	Electromagnet
.	. .

Which statement best compares a permanent magnet and an electromagnet?

a.	A permanent magnet has a fixed magnetic field strength, but the magnetic field strength of an electromagnet can be changed.
b.	The magnetic field lines from a permanent magnet emerge from the north pole, but they emerge from the south pole of the electromagnet.
c.	A permanent magnet requires an external source of energy, but an electromagnet produces its own energy.
d.	A permanent magnet has a north pole and a south pole, but an electromagnet only has a south pole.