The discovery of the electron Key Terms

cathode ray

A stream of electrons observed in vacuum tubes, which can be deflected by electric and magnetic fields.

electron

A subatomic particle with a negative charge, fundamental to the structure of atoms and responsible for electricity.

cathode ray

A stream of electrons observed in vacuum tubes, which can be deflected by electric and magnetic fields, indicating the presence of charged particles.

charged particles

Particles that possess an electric charge, such as electrons, which are fundamental to the understanding of cathode rays and their behavior in fields.

deflection of cathode rays

The change in direction of cathode rays when they pass through electric or magnetic fields, indicating the presence of charged particles.

charged particle behavior

The response of charged particles, such as electrons, to electric and magnetic fields, demonstrating their charge and mass properties.

cathode ray

A stream of electrons observed in vacuum tubes, which can be deflected by electric and magnetic fields.

electron

A subatomic particle with a negative charge, fundamental to the structure of atoms and responsible for electricity.

Thermionic emission

The process by which electrons are emitted from a metal when it is heated, providing evidence of the energy required to overcome the work function.

Work function

The minimum energy required to remove an electron from the surface of a metal, crucial in understanding thermionic emission.

Thermionic emission

The process by which electrons are emitted from a heated metal due to thermal energy overcoming the work function.

Work function

Work function means The minimum energy required to remove an electron from the surface of a metal. In Thermionic emission of electrons, use this term to connect Explain why heating can release electrons from metals. to evidence, observation and model change.

Thermionic Emission

The process by which electrons are released from a metal surface when it is heated, due to the electrons gaining sufficient energy to overcome the metal's work function.

Work Function

The minimum amount of energy required to liberate an electron from the surface of a metal into vacuum, typically expressed in electronvolts (eV).

Thermionic Emission

The process by which electrons are emitted from a heated material, typically a metal, due to thermal energy overcoming the work function.

Work Function

The minimum energy required to remove an electron from the surface of a material, measured in joules.

Specific Charge

The specific charge of a particle is defined as the charge per unit mass, typically expressed in coulombs per kilogram (C/kg).

Charge-to-Mass Ratio

The charge-to-mass ratio is a measure of the amount of charge per unit mass of a particle, calculated by dividing the charge (C) by the mass (kg).

Charge-to-mass ratio

The ratio of the electric charge of a particle to its mass, often used to determine the specific charge of electrons in electric and magnetic fields.

Electric field

A region around a charged particle where a force would be exerted on other charged particles, used to determine the charge-to-mass ratio of particles like electrons.

Specific Charge

The specific charge of a particle is defined as the ratio of its charge to its mass, typically expressed in coulombs per kilogram (C/kg).

Charge-to-Mass Ratio

The charge-to-mass ratio is a measure of how much charge a particle has per unit of mass, calculated using the formula q/m, where q is the charge and m is the mass.

Specific Charge

The specific charge of a particle is defined as the ratio of its charge to its mass, typically expressed in coulombs per kilogram (C/kg).

Experimental Uncertainty

Experimental uncertainty refers to the doubt that exists about the result of any measurement, often expressed as a range or percentage of the measured value.

Millikan's oil-drop experiment

An experiment that measured the charge of the electron by balancing the gravitational and electric forces on tiny charged droplets of oil.

Quantisation of charge

The principle that electric charge exists in discrete amounts, specifically as integer multiples of the elementary charge (the charge of a single electron).

Force balance

The condition where the sum of forces acting on an object is zero, leading to no acceleration.

Charge value determination

The process of calculating the electric charge of a particle using force balance in an electric field.

quantisation of charge

The concept that electric charge exists in discrete units, typically observed in the behavior of electrons.

Millikan's oil-drop experiment

An experiment that demonstrated the quantisation of electric charge by measuring the charge of oil droplets in an electric field.