What did Milikan find in his experiment?

[Okan]

Hi guys. I was searching about electricity lately and noticed something: Milikan determined the charge of an electron as 1.602*10^-18 coulomb(1 e=.1.602*10^-18 C). If he used the unit "coulomb" in his work, coulomb must exist in his times. 1 coulomb is defined as the charge of 6.24*10^19 electrons(1 C= 6.24*10^19). If i take the reverse of (1 C= 6.24*10^19), i get (1 e=.1.602*10^-18 C). In conclusion there was no need to do the oil drop experiment to find the charge of one electron if one coulomb was already defined in his times. Where am i wrong? Which is older, the definition of C or the oil drop experiment?

 

[mfb]

1 coulomb is defined as the charge of 6.24*10^19 electrons(1 C= 6.24*10^19).

It is not. This is actually a planned definition (just with more precision), but currently and historically the Coulomb had/has different definitions. At that time they did not even know about electrons.

By the way, Coulomb died around 1800, Millikan did his famous experiment in 1910.

 

[jtbell]

1 coulomb is defined as the charge of 6.24*10^19 electrons

Where?

One coulomb is currently (pun! :p) defined as the quantity of charge carried by a current of one ampere in one second. The ampere is defined in terms of the magnetic force between two current-carrying wires. These definitions have evolved over time, and I don't know the exact definitions Millikan used.

 

[Okan]

Hmmm... Is that so? Well, it's senseful. Thanks.

 

[pmacias]

Milikan's experiment, known as the oil drop experiment, was a pivotal moment in the history of science as it helped to determine the fundamental unit of charge, the charge of an electron. Through this experiment, Milikan was able to calculate the charge of an electron as 1.602*10^-18 coulomb (C). This value was significant as it provided a precise measurement of the charge of an electron, which was previously unknown.

It is important to note that the concept of coulomb (C) was already defined before Milikan's experiment. Coulomb is a unit of electric charge named after the French physicist Charles-Augustin de Coulomb. This unit was defined as the amount of charge transferred by a constant current of one ampere in one second. Therefore, it is not surprising that Milikan used this unit in his experiment to measure the charge of an electron.

To address the question of whether there was a need for the oil drop experiment if coulomb was already defined, we must understand that the oil drop experiment was essential in determining the precise value of the charge of an electron. While coulomb was already defined, the exact value of an electron's charge was still unknown. Milikan's experiment provided a more accurate and precise measurement of this value.

In conclusion, the definition of coulomb (C) predates Milikan's oil drop experiment. However, the experiment was crucial in determining the precise value of the charge of an electron and contributed significantly to the field of electricity and modern physics.