List out the evidences of quantisation of charge.

[physicsnet]

Homework Statement

List out the evidences of quantisation of charge.

Homework Equations

The Attempt at a Solution

Like, what evidence is there for charge quantisation?

 

[graphene]

The charge on atomic nuclei is an integral multiple of a proton's charge.
The charge of an ion too is an integral multiple of an electron's charge.

 

[AJ Bentley]

And don't forget the quantisation of the magnetic field in a superconductor.

 

[bp_psy]

http://en.wikipedia.org/wiki/Oil_drop_experiment
The Millikan Oil Drop Experiment.

 

[paranormal]

There are several pieces of evidence that support the concept of quantisation of charge:

1. Millikan's Oil Drop Experiment: In this famous experiment, Robert Millikan observed that the charges on oil droplets were always a multiple of a fundamental unit of charge, which he later determined to be the charge of a single electron. This provided strong evidence for the idea that charge is quantised in discrete units.

2. Coulomb's Law: Coulomb's law, which describes the force between two charged particles, is based on the assumption that charge is quantised. If charge was continuous, the force between two charged particles would not follow a simple inverse square relationship as described by Coulomb's law.

3. Photoelectric Effect: The photoelectric effect, in which electrons are ejected from a metal surface by shining light on it, also supports the concept of quantised charge. The energy of the ejected electrons is directly proportional to the frequency of the incident light, which suggests that the energy is quantised in discrete units.

4. Charge Conservation: The law of charge conservation states that the total amount of charge in a closed system remains constant. This implies that charge cannot be created or destroyed in discrete units, further supporting the idea of quantisation of charge.

5. Atomic Structure: The structure of atoms also provides evidence for the quantisation of charge. Electrons are arranged in discrete energy levels around the nucleus, and the movement of electrons between these levels involves the transfer of quantised amounts of energy.

Overall, these evidences and many others support the concept of quantisation of charge, which is a fundamental principle in modern physics.