Energy Levels Flashcards
Convert eV to J
E(in J) = E(in eV) x 1.60x10^-19
Convert J to eV
E(in eV) = E(in J)/1.60x10^-19
Where do electrons exist
on fixed energy levels
how does an electron get excited
by gaining energy and moving up one or more energy levels.
What is the condition for a photon to be absorbed by an electron?
the energy of the photon has to precisely match the difference between the current energy level and the one above.
energy levels formula
hf = E1 - E2 (in J)
What kind of interaction is a photon and an electron?
1 photon to 1 electron
what happens when an electron and a photon collide?
Some or all of Ek is given and any transition up to the Ek of the electron is impossible.
Define ionisation energy
The minimum energy required to remove an electron from the ground state of an atom.
What happens inside a fluorescent tube?
High voltage accelerates free electrons, these then collide with the mercury atoms, giving them energy and exciting them to higher energy levels, when the electrons cascade down the energy levels they emit a photon of UV light for each energy level dropped.
What is special about the UV photon emitted in a fluorescent tube?
Its energy is the energy difference between the two energy levels that the electron dropped down.
What is the purpose of the powder coating in a fluorescent tube?
It absorbs the UV photon and excites the electrons to higher energy levels causing them to cascade down the energy levels and emit photons of different frequencies to create white light.
