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Name: _________________________
Faraday's Electromagnetic Induction Lab
Purpose:
The purpose of this lab is to help you develop an understanding of how electricity can be generated
using a magnetic field. It will also help you understand how varying conditions influence the amount
of electricity generated, such as the number of coils, the area of the coils, the speed of the
magnet, the polarity of the magnet and the strength of the magnetic field.
Procedure:
Click on the link below to the simulation “Faraday’s Electromagnetic Lab” on the Physics Education
Technology (PhET) website developed at the University of Colorado at Boulder.
http://www.colorado.edu/physics/phet/simulations/faraday/faraday.jnlp
Bar Magnet – General Magnetism
1. Click on the "Bar Magnet" tab if you are
not already there. You should see a bar
magnet and compass on the screen.
Please note that the color red refers to
North Pole of the magnets and white
refers to South Pole. Move the compass
around the magnet and then move the
magnet around the compass.
Click and unclick the various controls in
the upper right corner of the page to
see the different possible views.
A. As the compass and magnet are moved around, in what direction does the North
Pole of the compass want to point?
B. When there are no other magnets around and the compass is only influenced by the
Earth’s magnetic field, the red compass needle points in the direction of the
Earth’s north geographic pole. From this observation, which magnetic pole is
at/near the Earth’s North Pole?
Here is a representation of the Earth and its magnetic field from Wiki.
Pickup Coil – General Electromagnetic Induction
1. Click on the "Pickup Coil" tab. Observe what
happens when you move either the magnet
or the light bulb and coil.
A. By adjusting the controls on the right hand side of the screen, describe how you
should change each of the parameters below to make the bulb grow brighter.
- Speed of motion:
- Number of loops:
- Loop Area:
B. Under what conditions does the light bulb not shine?
C. What parameter (that causes current to flow and the light to shine) is affected by
the speed, number of loops and loop area?
D. Write Faraday’s Law.
Electromagnet
1. Click on the "Electromagnet" tab. Observe
what happens when you move either the
magnet or the electromagnet.
2. Align the coils of the electromagnet and the compass, so that the compass is directly to the
right of the coils. Using the slider on the batter, change the voltage from +10 V on the right
side of the battery to +10 V on the left side of the battery. What is the effect on the
compass? Why?
3. Change your current source from DC to AC and describe what the compass does.
4. Observe the electrons in the AC current source and compare their movement to those in the
DC current source. Explain the difference between DC and AC in terms of electron
movement.
Transformer
1. Click on the "Transformer" tab. The last tab showed us that current can create a magnetic
field. Move the electromagnetic back and forth and observe what happens.
2. Change the current source to AC source. Observe what happens even while the
electromagnet is not moving. Why does the light bulb light up?
Generator – Putting it All Together
1.
Click on the "Generator" tab. Turn on the water faucet and observe what happens. Adjust
the controls to maximize the light’s brightness. Fill in these values below.
Turbine (Magnet) Strength
Loop Area
_______
_______
Number of loops
RPMs
_______
_______