How is it possible to have a beam of red light that is brighter than a beam of blue light, when blue-light photons are more energetic than those of red light?
2007-02-19 09:04:43 · 3 answers · asked by stephen445 1 in Science & Mathematics ➔ Astronomy & Space
Brightness is a measure of how many photons are present, not how energetic they are. A bright light emits many photons, while a less-bright light emits less. I think that humans perceive all photons equally--we see the photon and its wavelength and frequency, not its energy, although I am not sure about that.
2007-02-19 09:13:08 · answer #1 · answered by enigma2029 2 · 2⤊ 0⤋
It is possible in two ways:
1. For example, let's assume that a red beam photon has 1 joule of energy and a blue beam photon has 3 joules of energy. Now, the blue beam photons arrive at the rate of 10 per second, so we have 30 joules of energy per second. If the red beam photons arrive at the rate of 40 per second, then we will have 40 joules of energy per second, thus more energy thus a brighter beam.
2. If the source of the red beam is much closer than the source of the blue beam, then the red beam will be brighter.
2007-02-23 16:30:21 · answer #2 · answered by Tenebra98 3 · 0⤊ 0⤋
You are simply talking about more light when talking about brightness. A slow moving river might be less energetic then a firehose but it holds a lot more water. Same with an intense beam of red light compared to a less intense beam of blue light.
2007-02-19 17:18:14 · answer #3 · answered by Roman Soldier 5 · 3⤊ 0⤋