Wave particle duality and De Broglie wavelength

What is meant by wave particle duality

Every quantum entity exhibits both a wave like nature and a particle like nature

Is light a particle or a wave

Light is neither a particle or a wave. We can describe it acting like one or the other to explain the results of different experiments

Double slit experiment

Photoelectric effect

Describe how electron diffraction provides evidence for the wave nature of particles.

A beam of electrons is fired at a thin graphite target

A diffraction pattern of concentric rings is observed on the screen

This shows electrons can exhibit wave like behaviour

The wavelength calculated agrees with de broglies wavelength.

What’s the pattern for electron diffraction

Concentric rings

How does increasing the potential difference increase the speed of the electron in electron diffraction

Negative charges repel and increasing voltage increases negative charge at the cathode

What’s the equation for working out de Broglie wavelength

Lambda = h / mv

Do faster or heavier particles or slower or lighter particles have the longer wavelength

Slower or lighter

What are the two rules for electron diffraction

Separation of atoms in the crystal the electrons are fired through have to be larger than the wavelength of the atom.

Separation cannot be more than one order of magnitude greater than wavelength