Who conducted experiments to determine the charge carried by an electron?
Answered on
The experiments to determine the charge carried by an electron were conducted by the American physicist Robert A. Millikan. The most famous of these experiments is the oil-drop experiment, which was performed by Millikan and his graduate student, Harvey Fletcher, in 1909. In this experiment, Millikan was able to measure the charge of an electron with great precision.
The oil-drop experiment involved spraying tiny oil droplets into a chamber and allowing them to pass through a hole into an area subjected to a uniform electric field. By adjusting this electric field, Millikan could balance the gravitational force on the oil droplet with the electric force. Since the force of gravity depends on the mass of the oil droplet (which can be calculated if the density of the oil and the size of the droplet are known), and the electric force depends on the charge of the droplet and the strength of the electric field, Millikan was able to deduce the charge on the droplets. Through careful observation and measurement of many oil droplets, he noticed that the charge on the droplets was always a multiple of a certain smallest value. This smallest value, which he calculated to be approximately 1.6 x 10^-19 coulombs, is the charge of a single electron. Millikan's accurate determination of the electron charge was a significant milestone in physics, and for this work, he was awarded the Nobel Prize in Physics in 1923.
Understanding what an electron is and its significance in chemistry and physics can be fascinating. An electron is a subatomic particle that has a negative charge and is found outside the nucleus of an atom. Electrons play a crucial role in electricity, magnetism, and chemical bonding. They are responsible for the electrical properties of materials and are at the heart of many modern technologies. The quantization of electric charge, as evidenced by the charge of the electron being a fundamental unit of charge, underpins the discrete nature of electric charge, which is a cornerstone of atomic theory and quantum mechanics.