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 = 2D 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 |
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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 |
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d) Constant Current Power Supply, DPS-175
e) Gaussmeter, DGM-202 or DGM-102
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