Bodhi shines faint ultraviolet light on a freshly cleaned zinc plate. Electrons leave it one by one. Each leaving electron collected its escape energy from where?
The photon is a whole lump; an electron is what absorbs it. This lesson states the absorption rule that the rest of this topic stands on.
In the photoelectric effect, the energy that frees an electron arrives as a single photon.
One photon in, at most one electron out: each absorption is a one-on-one event.
An electron cannot save up energy across several photons. Two weak lumps never add up to one strong one.
The whole effect runs on this rule: because each electron absorbs the energy of a single photon in one lump, and cannot pool energy from many photons, every ejection traces back to exactly one absorbed photon.
An electron in Bodhi's zinc absorbs one ultraviolet photon whole: one lump, delivered in full, to one electron.
An electron leaves a zinc plate under ultraviolet light. How many photons supplied its energy?
The energy that frees an electron arrives as one photon.
The electron absorbs that photon's energy in one lump.
It cannot add energy from any other photon to the lump.
Exactly one photon supplied it, absorbed whole.
Over one minute, an electron in a metal is reached by sixty faint photons, one each second. Can it gather their energy together to escape?
Each absorbed photon delivers one lump, on its own.
An electron cannot pool energy from many photons.
Whatever one lump can do, sixty separate lumps spaced out can do no more at any one moment.
No. The electron cannot pool the sixty lumps; each photon's energy stands alone.
An electron is ejected from a metal plate by light. How many photons' energy did it absorb to leave?
Gwenno says: 'Each ejected electron got its energy from a single photon, absorbed in one lump.' Is Gwenno correct?
Hamish says: 'In dim light, an electron can save up energy from many weak photons until it has enough to escape.' Is Hamish correct?
Which statement is the absorption rule of the photoelectric effect?
Two faint photons reach the same electron a few seconds apart. What is the most energy the electron can put toward escaping at any one moment?
In one second, 40 electrons are ejected from a plate. How many absorbed photons do those ejections trace back to?