Particle theory of light

Cards (13)

What is the alternative model to the wave theory of light?
The particle theory of light
How does the particle theory of light describe the composition of light?
It describes light as consisting of small packets/quanta of energy, called photons
What equation is used to calculate the energy of light photons?
E=hf
What is an electronvolt?
The energy transferred when a single electron is moved through a potential difference of 1 volt
How many joules is an electronvolt equal to?
$1.6 ×10^-19$
What is the photoelectric effect?
When electrons are emitted from the surface of a metal due to light being incident on it
What are the requirements for photoelectrons to be omitted from a metal?
The incident light must have a frequency higher than the threshold frequency
As one photon must transfer sufficient energy to one electron to allow it to overcome the metals work function and be released
What is a metals work function?
The minimum energy needed to liberate an electron from its surface
What can be said about the KE of the emitted photoelectons?
They will be emitted with a range of kinetic energies up to a maximum value
What equation can be used to calculate the maximum KE of a photoelectron?
$E=$ $hf-workfunction$
What does electron diffraction provide evidence for?
The wave behaviour of matter
What is the name of the wavelength of matter?
The de broglie wavelength
How do you calculate the de broglie wavelength?
Wavelength = h/mv