Apparatus for Measurement of Susceptibility of Paramagnetic Solids by Gouy’s Method

In the Gouy’s method of susceptibility measurement, the solid sample in the form of a long cylinder (area of cross section A) is hung from the pan of a balance and is placed such that one end of the sample is between the pole-pieces of the magnet (field H ) and the other one is outside the field. The force exerted on the sample by the inhomogeneous magnetic field is obtained by measuring the apparent change (D m ) in the mass of the sample. The susceptibility c is given by
c = 2 mg/AH2

If the sample is in the form of powder, it is filled in a long nonmagnetic tube which is then suspended from the pan of the balance..

Description of the experimental setup

a) Scientific Balance, KSB-07

Capacity 200 gms
Sensitivity 1/10 mg. by vernier
Beam Hard Bronze/ Brass
Arrestment Circular, falling away type
Air Damping Very quick and positive, beam coming to rest in 2-3 sec
Chainomatic Device A gold plated chain is suspended from the beam with its other end screwed on the rotating drum on which a scale graduated from 0 to 10 div each division representing 1mg is installed. By the movement of this scale before a vernier, reading upto 1/10th mg is taken

b) Sample in the form of a long rod

Set of 4 samples,2 each of Ebonite and wood

c) Electromagnet, EMU-75T

Pole Pieces 75mm tappered to 25mm
Mag. Field 20KG at 6mm airgap
Energising Coils Two of approx. 13W each
Power 0-90Vdc, 3A, for coils in series
0-45Vdc, 6A, for coils in parallel

d) Constant Current Power Supply, DPS-175

e) Gaussmeter, DGM-202 or DGM-102

The experimental set-up is complete in all respect



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