If an irregularly shaped conductor is charged, the charge on it is not evenly distributed.

Some potions will carry more charge than others.

The proof plane can be used to investigate the distribution of charge on a charged conductor. It is an insulatirig handle attached to a conducting disc (figure below). When the proof plane is placed in contact with a charged conductor, it collects charge from the surface of the conductor. The amount of charge collected depends on the quantity of charge on that particular portion of the conductor.

Therefore the proof plane is used to transfer shall amounts of charge from a charged object to an electroscope. The greater the divergence of the leaf, the larger the amount of charge collected.

The greater the divergence of the leaf, the larger the amount of charge collected.

                                    Fig; the plane proof

CHARGE DISTRIBUTION ON A HOLLOW PEAR-SHAPED CONDUCTOR

The charged hollow pear-shaped conductor is shown in figure below.

A neutral proof plane is placed in contact with different sections of the conductor. It collects some charge from the section and the amount of charge collected is directly proportional to the concentration of charge (charge density) at that section.

Each time the proof plane is removed; it is placed on the cap of a neutral gold-leaf electroscope. The angle of divergence of the leaf of the electroscope is measured using a protractor in each case.

When the electroscope is used once, it is discharged by earthing.

The following observations are made.

1. The greatest divergence occurs when the proof was placed on the sharpest section of the conductor, I.e. at A.
2. There was no divergence when the proof plane was placed on the inside surface of the conductor, I. e. at D.