Electroscope

Electroscope, instrument for detecting electrostatic charge. It works on the principle that 2 bodies having the same charge will repel each other. In the gold leaf electroscope the 2 bodies are a rod and a piece of gold leaf, or two pieces of gold leaf. If the electroscope can be used to measure the charge, it is also known as an electrometer. The quadrant electrometer consists of a hollow circular box divided into 4 quadrants. A hollow plate inside the box is deflected by the quadrants when a charge is applied, and the amount of deflection gives the quantity of electrostatic charge. Other kinds of electrometers include instruments that depend on the deflection of a quartz fiber in an electrostatic field and modern instruments containing electronic amplifiers. Electroscopes can detect and measure the intensity of ionizing radiations such as X-rays.