Hamish slides a dimmer and a red porch light climbs from dim to blazing. The color never changes. In the photon model, what did 'brighter' actually change?
You have seen intensity defined as the energy light delivers to a surface each second. The photon model now reads that brightness dial in lumps.
A brighter lamp delivers more energy to the same surface each second. That is what intensity measures.
In the photon model that energy arrives as photons. The light's color has not changed, so the energy of each photon has not changed.
Each photon is unchanged. Raising the intensity never makes any single photon stronger.
Hamish's brighter red lamp sends more red photons each second, each photon with unchanged energy.
The two dials stay separate. Frequency sets the size of each lump. Intensity sets how many lumps arrive each second.
A red lamp over a desk is turned from dim to bright, its color unchanged. Describe the change in the photon stream.
The color is unchanged, so the frequency is unchanged.
The energy of each photon follows the frequency, so each photon is the same lump as before.
The lamp now delivers more energy each second, so it must be sending more photons each second.
More red photons arrive each second; each photon's energy is unchanged.
A violet night-light is dimmed to a quarter of its brightness. What happens to its photons?
Dimming lowers the energy delivered each second.
The color is unchanged, so each photon's energy is unchanged.
So the lamp sends a quarter as many photons each second.
A quarter as many violet photons arrive each second; each photon's energy is unchanged.
A lamp of one color is turned brighter. How does the stream of photons reaching the wall change?
Farid says: 'Turning the lamp brighter makes each photon carry more energy.' Is Farid correct?
Bodhi says: 'A brighter lamp of the same color sends more photons each second.' Is Bodhi correct?
In the photon model, what does raising a beam's intensity do, with the color unchanged?
A blue reading light is dimmed, its color unchanged. Which pair of changes follows?
Two floodlights of the same color shine on one wall: one dim, one bright. Which quantity differs between their photon streams?