What does it actually mean for an electron to be excited?
60471
Electron shells in atoms: What causes them to exist as they do?
58775
What exactly does the *frequency* of a photon mean?
70966
Where is the evidence that the electron is pointlike?
52598
How can I interpret "energy" in signals?
131782
Which charge actually moves to constitute current? Positive or negative?
21187
What happens in electron-electron collisions?
123657
Why do physicists think that the electron is an elementary particle?
91879
Atomic Physics: stimulated emission
76757
How do photons know they can or can't excite electrons in atoms?
17787
Photoelectric Effect, Why can't two quanta interact with an electron at the same time?
40542
From where electrons flow to make a bulb light?
53287
Why is charge of the electron negative?
41041
Does a photon instantaneously gain $c$ speed when emitted from an electron?
87284
What enables protons to give new properties to an atom every time one is added?
74797
Why are there $1 / 1.602176634 \times 10^{-19}$ electrons in a coulomb?
20997
Can an electron jump to a higher energy level if the energy is insufficient or exceeds the $\Delta E$?
52248
Why does the direction of a dipole moment go from negative to positive charge?