College Physics II Magnetic susceptibility EPCC
Objective: Understand magnetic permeability and susceptibility of various materials.
Note: Measurements must be in MKS units.
Part 1: Magnetic types
Review the link to better understanding of the
three types of magnetism.
https:
youtu.be/u36QpPvEh2c
This link provides an additional reference for
this lab:
https:
pubmed.ncbi.nlm.nih.gov/ XXXXXXXXXX
Qualitative: Paramagnetism
Refer to figure 1 for the following: Prepare a paperclip and 3 to 5 pencil leads with masking tape.
Fill a bowl of water, and allow the paperclip to float on the water. Gradually
ing the magnets
close to the floating paperclip and note the reaction. You should see an attractive motion. Its
magnetic susceptibility would be a positive value if measured.
Qualitative: Diamagnetism
Refer to figure 1 for the following: Remove the paperclip from the water, and place the pencil
leads (i.e. graphite) on the water. Slowly
ing the magnets close to the pencil leads and note the
eaction. You should see a very gradual repulsion. Its magnetic susceptibility would be a
negative value if measured.
(a) (b)
Figure 1: Magnetic test: (a) graphite (i.e. pencil leads) and paperclip have tape fastened
underneath them in order to float. (b) the items are placed in water where a magnet is placed
nea
y. Paramagnetism or diamagnetism of each item are exhibited when the magnet is
placed near them.
https:
youtu.be/u36QpPvEh2c
https:
pubmed.ncbi.nlm.nih.gov/ XXXXXXXXXX
College Physics II Magnetic susceptibility EPCC
Part 2: Magnetic Susceptibility
Setup
Refer to figure 2 – CAUTION WITH MAGNETS: Split in half the magnet set, and place each
half 2.0 cm away from each other. Secure them well with tape.
Refer to figure 3 & 4: Place your phone no more than 4.0 cm perpendicularly from the magnets.
Prepare the specimens for testing their magnetic susceptibility. Set the the PhyPhox® app to the
magnetometer and select the absolute option.
Magnetic susceptibility
Equation 1 describes the magnetic susceptibility of any material. The µ and the µo are the
elative magnetic permeability of the material and of free space respectively. We will measure
the each value by measuring the magnetic fields of each. Since the permeability is directly
proportional to the magnetic field, we can make the ratio of the magnetic field of the material and
free space to be µ/µo.
μ
μo−1 = χ
where: B
Bo
= μμo
Equation for calculating
susceptibility.
(a) (b)
Figure 2: Neodymium magnets are evenly distributed. Each half is separated by 2.0
cm (a) and securely taped so as not to move (b).
College Physics II Magnetic susceptibility EPCC
Quantitative: Susceptibility
Be sure to be removed from any outside sources of magnetism: Make sure you export and plot
your data. Keep track of the items measured and their magnetic response on your plots.
Refer to figure 5: Measure the ambient
magnetic field for 6 - 8 seconds, and pause
the app. Record this in table 1 and restart the
app. Next select an item to test, and place it
etween the two magnets, making sure you
do not touch either magnet. Hold your item
etween the magnets for 5 seconds, and
emove it carefully such as not to touch either
magnet. Measure the magnetic response
using PhyPhox® app and record in table 1. If
the magnetic field measurement for the item
is unnoticeable or weak, put a question mark
oth in the Paramagnetic and Diamagnetic
columns. Repeat the process until you have
tested all the items. The magnetic plot profile
you make should look similar to figure 5, with
variations in magnetism due the material
interaction with the magnetic field.
(a) (b)
Figure 4: (a) Select the Magnetometer option on PhyPhox
(R). (b) be sure to select the ‘absolute’ option.
(a) (b)
cellphone
4.0 cm
Figure 3: (a) Items to be tested - from left to right: Peso or an international coin, quarter,
penny, pencil leads, paperclip, CR2032 battery, and LED bulbs. If an international coin is
not available, the instructor will provide a viable substitute. (b) Cellphone is placed 4.0 cm
from the edge of the magnets. DO NOT place any closer.
College Physics II Magnetic susceptibility EPCC
Table 1. Magnetic Susceptibility of Materials
Item µ µo χ Paramagnetic (Y/N) Diamagnetic (Y/N)
Questions – answer each question within 3 sentences.
1. Define precisely what is magnetic susceptibility. What does a material’s negative or
positive susceptibility tell you about that material?
2. What do you notice about the magnetic susceptibility of the paperclip compared to the
other items? Is it positive or negative? Which had the strongest and weakest
susceptibility value?
3. Refer to the links and other references included in this lab to help you with your answer:
How does understanding paramagnetic and diamagnetic properties of materials allow
you to understand the internal structure and physiology of the human body or any living
creature? https:
pubmed.ncbi.nlm.nih.gov/ XXXXXXXXXX
Figure 6: Results from a susceptibility test. The
aseline magnetic field strength (red) will be used
to calculate the µo. The induced magnetic field
strengths of the materials (purple) will be used to
calculate the µ.
Baseline/ambient
induced magnetic
field increase
induced magnetic
field decrease
Figure 5: Choose the 'absolute'
option in the 'magnetometer'
function to get peak/maximum
magnetic field strength.
https:
pubmed.ncbi.nlm.nih.gov/ XXXXXXXXXX
College Physics PhET Magnetism Simulations EPCC
Goal : Learn about magnetism. Remember to answer concisely within 3 sentences.
Use the following link to access the PhET simulation:
https:
phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation=magnets-and-
electromagnets
Bar Magnet:
Select the Bar Magnet tab; refer to figure 1. Be sure to
click on the See Inside Magnet and Show Field Meter
uttons on the right hand menu; refer to figure 2. Place
the magnet meter at the center of the compass; refer
to figure 2. Adjust the magnet strength to 50% and
move the bar magnet around the compass making
sure the keep that same distance away from compass
as you go around it. Increase the bar magnet strength
to 100% and repeat the same movement around the
compass. Now move the bar magnet close to
compass, then as far away from the magnet as
possible. Be sure to take note of the strength of the
magnetic field as you conduct this lab.
Questions:
1. How does the strength of the magnetic field
vary as you move it around the compass?
2. How does the magnetic field vary as you
ing
the magnet close to and away from the
compass?
The Electromagnet
Select the Electromagnet tab; refer to figure 3. Align your battery-loop system with the magnetic
field meter and compass. Select the all the options in the right hand menu, making sure you are
at the maximum battery strength; refer to figure 4. Move the battery-loop system around the
compass and not the changes in the magnetic field strength. Then decrease the number of loops
and repeat the same motion. Return to the number of loops that you started while reducing the
attery strength by half. Be sure to note the changes you witness during this experiment.
Figure 1
Figure 2
https:
phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation=magnets-and-electromagnets
https:
phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation=magnets-and-electromagnets
College Physics PhET Magnetism Simulations EPCC
Questions:
3. Refer to your textbook and notes: Explain how a magnetic field is being produced with
moving charges.
4. How does changing the number of loops and adjusting the battery strength affect the
magnetic field produced?
Figure 3 Figure 4
College Physics PhET Magnetism Simulations EPCC
Change the following parameters of the resistor according to the settings below. Remember to
eset the simulation for every case:
1. Vary the length of the resistor, keeping all things constant
2. Vary the cross-sectional area, keeping all other things constant
3. Vary the resistivity, keeping all other things constant
Problems:
1. Make notes on what you learned from this simulation. Write a synopsis (no more than 5
sentences) on what you learned from the simulation.
2. Calculate the maximum and minimum conductivity based on the maximum and minimum
esistance you got from this simulation. What type of relationship does the resistivity has
with conductivity of a material?
Biophysics – electrostatics PBL
Lucus, the flying spide
2
Some links
https:
youtu.be/v7H_Or9Nr5I
https:
youtu.be/x4ed7Y5Xffg
3
Figure: Excerpt from (Gorham, 2013)
Ai
orne spiders
Lucas’s cousin, Spiffy.
Spiffy the spider decides to take flight
(yay physics)! Spiffy wants to achieve a height of
1.0x103 m. Granted He just ate his favorite fly
soup, so he’s slightly massive (0.25 mg).
How much charge would he need? Does your answer
make sense (hint – look at the graph)
What’s Spiffy’s Coulomb force at 1.0 km?
How much work was done to get Spiffy up there?
What’s the estimated electric field and electric
potential at that altitude?
Charge needed to get to altitude:
Q = mg
Eo
eαH
H = altitude,
α = 3.0 x10−4 m−1
Electric field at altitude:
E(H )= Eo e
−α H
Eo = 120.0Vm
−1
Look,
equations!
https:
arxiv.org/pdf/1309.4731v1.pdf
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