The Kerr cell consists of the nitrobenzene being examined placed in an insulating container with two electrodes attached to supply necessary electric field. The container is usually a strong optical glass and the electrodes are constructed so as to supply a very uniform electric field when a potential difference is applied.

During the experiment, voltages for which luminous intensity becomes maxima and minima are observed. At a voltage of near 2600 Volt the luminous intensity reaches a maximum for the first time. In this case the normal and extraordinary beams are phase-shifted by 180°. 2600 volt is therefore the “half-wave voltage”.

By plotting the square of the applied voltage versus the phase shift between normal and extraordinary beam, it can be shown that the relation between the two quantities are approximately linear. From the slope of the straight line the Kerr constant can be calculated. The kerr constant of nitrobenzene is found to be 4.55 X 10^-12 mV^-2 and the accepted value is 4.4 X 10^-12 mV^-2.