problem with the Rutherford model: electron is undergoing acceleration - would emit energy in radiation and spiral into the atom
but this doesn't happen…
Bohr:
(electric force = centripetal force → mv^2/r = ke^2/r^2 → mv^2=ke^2/r)
| Observations from the experiment | Problems with wave model explanation |
|---|---|
| When light is incident on the metal plate, electrons can be emitted. | |
| (these are called photoelectrons) | No problem: light waves can pass on energy to electrons so they escape the surface. |
| The electrons flow through a sensitive galvanometer in a complete circuit and small currents can be measured. | No problem: current flow is a consequence of energetic electrons crossing the gap |
| Increasing the voltage across the gap (in the opposite direction to electron flow) reduces recorded current. | |
| The Voltage that just stops the highest energy electrons and reduces the current to zero is called the stopping voltage Vs. | No problem: this is just the definition of stopping voltage. |
