Physics Practical Demo

8/10/2019 Physics Practical Demo

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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/


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THANK YOU.

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Physics Practical Demo