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PHYSICS LAB
PRESENTATION
By - Manmeet Singh
480/IC/11, ICE-2
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AIM
To determine the susceptibility arising due to water
in the solution of manganese chloride (MnCl2).
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PRINCIPLE
When a solution of a paramagnetic salt (here, MnCl2)
is taken in a tube and is placed between the poles of
a magnet, there is a rise in the liquid level. A
measurement of this rise enables to determine the
susceptibility of the solution.
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APPARATUS REQUIRED
An electromagnet Funnel
Power Supply Weight box
Travelling Microscope Flask
Gaussmeter with search coil Weighing bottle
Water
Physical Balance
U-tube
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THEORY
The magnetic field between the wedge-shaped polepieces varies rapidly along the vertical direction.
Thus, the force on the solution is vertical. The force
on a substance of volume V situated in a non-uniform
magnetic field in a place where the field strength is H
is given by:
F=1/2(k-k0) dH2/da*V
Where k is the magnetic susceptibility of thesubstance.
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k0is the magnetic susceptibility of the surrounding
medium.Generally surrounding medium being air, (k0=0), thus
the above relation becomes:
F=
1
/2(k)dH
2
/dx*VConsider the experimental set-up and let the position
of the solution in funnel be D and that in the tube be A.
On applying certain field the level of the solution shifts
from D to C and corresponding from A to B.
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The change in the level (A to B) of the solution is say, h.
Areas of the cross-section are: a,a. The change in thelevel (D to C) be d. Therefore,
ad=ah
Since the corrected height is:h+d=(1 +
a/a)h
This is the height of the liquid column supported by
the forces arising from the magnetic field. If rho isthe density of the solution and g is the acceleration
due to gravity, then the weight of this column is:
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(1 +a/a)hga. Let O be a section where the field is
negligible. Let x be the vertical coordinate of O andthus, the force on a liquid element of the volume adx
above the point O is given by:
F=1/2(k)dH
2/dx*(adx)
The force on the entire liquid above the point O is:
F=1/2(k)aH1
2
H1is field intensity at upper level. It is this force
which supports the weight of the column obtained
above. Thus,1/2(k)aH1
2= (1 +
a/a)hga
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If a
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PROCEDURE
Clean the U-tube with warm chromic acid.
Fill it with the solution of MnCl2.4H2O (of prepared
concentration).
The narrow end of the U-tube is placed between thepole pieces of the electromagnet.
The level of meniscus is taken down.
The current(magnetizing) is noted down by means of
the ammeter (attached to the power supply).
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The current is increased and the level of meniscus is
found to alter. Note the value of levels forcorresponding magnetizing current.
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OBSERVATIONS
S. No. Current
(A)
Magnetic
Field (H1)
(Gauss)
(H1)*(H1) Initial
Height
(A)
Final
Height
(B)
H=B-A
1. 0.5 1.35 1.8225 5.662 5.666 0.04
2. 1.0 2.7 7.29 5.662 5.677 0.15
3. 1.5 4.07 16.356 5.662 5.695 0.33
4. 2.0 5.44 229.593 5.662 5.719 0.575. 2.5 6.4 40.96 5.662 5.739 0.77
6. 3.0 7.36 54.1649 5.662 5.745 0.83
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GRAPH
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0 5 10 15 20 25 30 35 40 45
Plot of h v/s H12
H12
h
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RESULT
The volume susceptibility at room temperature is:
0.0378
The mass susceptibility at room temperature is:0.0108
The plot of h (y-axis) and H1
2(x-axis) is a straight line.
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PRECAUTIONS
Zero error should be checked in travelling
microscope.
The cross wire of the travelling microscope should be
placed right on the top of the upper meniscus of
solution before taking the reading.
The probe of the Gaussmeter should be held stablywhile measuring the value of magnetic field.
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ADVANCED APPLICATIONS
Determination of human iron stores or reserves in
the body.
Determination of magnetite content through the use
of magnetic susceptibility in large diameter holes.Use of magnetic susceptibility probes in the
treatment of cancer.
Development of new ferromagnetic catheters for
Magnetic Resonance Imaging (MRI).
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BIBLIOGRAPHY
www.wikipedia.com
www.tutorvista.com
www.physicsforums.com
Physics lab manuals
http://www.wikipedia.com/http://www.wikipedia.com/http://www.tutorvista.com/http://www.tutorvista.com/http://www.physicsforums.com/http://www.physicsforums.com/http://www.physicsforums.com/http://www.tutorvista.com/http://www.wikipedia.com/8/10/2019 Physics Practical Demo
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THANK YOU.