Quantum physics

Question 1

What is a photon

Answer 1

A discrete packet of electromagnetic energy

Question 2

What is the photoelectric effect

Answer 2

When a source of light with frequency equal to or greater than the threshold frequency of a metal is incident on the metal, free electrons are exited and are emitted from the metal. To increase the kinetic energy of the electrons emitted, the frequency of the incident light must be increased. To increase the amount of electrons emitted, the intensity of the light must increase. Photoelectric effect is a one to one interaction, meaning 1 photon is incident on 1 electron.

Question 3

Electron diffraction

Answer 3

Electrons are fired from an electron gun at a piece of graphite, where the gaps between atoms are similar to the wavelength of electrons, causing them to diffract as they pass through. The electrons create a diffraction pattern on the screen as they pass through the graphite, demonstrating its wave-particle duality.

Question 4

What is the de broglie wavelength

Answer 4

Wavelength is equal to plancks constant divided by momentum of the particle. Only applicable to particles.