B.Sc IIIrd year Apparatus : Hall probe (ge crystal of thickness 0.4-0.5 mm) mounted on a wooden stand, another Hall probe (In-As crystal), fluxmeter (a gauss meter), electromagnet with pole pieces nearly 75 mm, in diameter and producing magnetic field of intensity nearly 10000 gauss in between the pole pices, a constant current power supply for the electromagnet, Hall effect set up provided with a constant current power supply connected with a rheostat and millivoltmeter (range 0-200 mV) and milliammeter (range 0-20mA)