Quantum Phenomena Flashcards
What is work function?
Work function is the minimum energy required for an electron to be released from a metal
Explain why the kinetic energy of the emitted electrons has a maximum value
- The energy is the same in all photons
- The energy required to remove the electron varies
Unit for work function
Joule
Equation for Ke
Ke=1/2mv^2
Equation for De broglie wavelength involving mass
Lambda = Planck’s constant/Mass x Velocity
Equation for De broglie wavelength involving momentum
Lambda = Planck’s constant/Momentum
How would increasing the frequency of light affect electrons being emitted
The maximum kinetic energy would increase due to the frequency of the photons increasing their energy
How would increasing the intensity of light affect electrons being emitted
The rate of photons emitted increases as there are more photons hitting the surface of the metal.
What is meant by validated evidence
The experiment needs to be performed and then the results of the experiment needs to be proved and repeatable
Explain why the emitted electrons have a range of kinetic energies up to a maximum
value
The energy of photons stays constant and since the interaction between photons and electrons is one to one, the maximum kinetic
In a fluorescent tube, explain how the mercury vapour and the coating of its inner surface
contribute to the production of visible light.
Mercury at low pressure becomes excited by the electrons that collide with the atoms, the mercury atom then produce UV radiation, the coating of the flourescent tube absorbs the UV radiation and emits it as visible light, which makes the excited electrons cascade down energy levels.
What is meant by ground state?
When electrons are at their lowest energy state
Explain the difference between excitation and ionisation
In both cases the electron recieves energy while excitation moves the electron to a higher energy level and ionisation occurs when an electron recieves enough energy to leave the atom
Equation for photoelectric effect
E = hf