Inthe 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 ( Dm ) in the mass of the sample. The susceptibility c is given by

c= 2Dmg/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.

The set up consists of the following:

(a) Scientific Balance

The set up consists of the following:
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 Device 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 samples

(c) Electromagnet

Pole Pieces: 75mm tappered to 25mm
Mag. Field: 20KG mm 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

(e) Gaussmeter