## Intensity vs energy

$c=\lambda v$

AJ Manzano 3K
Posts: 16
Joined: Fri Sep 28, 2018 12:25 am

### Intensity vs energy

What exactly is intensity in comparison to energy? I know it’s like making the lights brighter while the type of light stays the same. So how does it become brighter if the energy doesn’t increase? Energy is related to wavelength, but how does intensity relate?

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### Re: Intensity vs energy

Intensity is the amount of energy delivered per unit time per unit area.

Erin Kim 2G
Posts: 75
Joined: Fri Sep 28, 2018 12:26 am

### Re: Intensity vs energy

intensity directly relates to the number of photons in the light. So if the number of photons increases, then the intensity increases/ gets brighter even if the type (wavelength or frequency) of photon did not change.

904936893
Posts: 62
Joined: Fri Sep 28, 2018 12:29 am

### Re: Intensity vs energy

Intensity is increasing the amplitude of the wavelength, so making it larger or smaller. When light is acting as a particle, increasing the intensity is just increasing the amount of photons (not the energy per photon). The reason why intensity was significant was because in the photoelectric experiment, the scientists believed increasing the intensity would cause electrons to be excited, because it would be like hitting the metal that they were trying to eject electrons from with a 'large' wave vs. a 'small' wave. However, since light was acting as a particle, increasing the intensity only increased the amount of low-energy photons that were hitting the metal, but each individual photon didn't have enough energy on it's own to eject an electron. Once you have a photon that has enough energy (based on wavelength/frequency), then increasing the amplitude will cause more electrons to be ejected, but they will all still have the same amount of energy.

Brice McKeown 3D
Posts: 35
Joined: Fri Sep 28, 2018 12:25 am

### Re: Intensity vs energy

Just read over this in the book and thought it may ne helpful... intensity is about the number of photons, and when looking at E=hv, the E is the amount of energy of each photon individually.

WilliamNguyen_4L
Posts: 65
Joined: Fri Sep 28, 2018 12:28 am

### Re: Intensity vs energy

Intensity is the amount of photons while the energy of the light described as E=hv is the amount of energy per individual photon.

kimberlyrose1G
Posts: 44
Joined: Fri Sep 28, 2018 12:27 am

### Re: Intensity vs energy

Intensity is the amount of photons, while energy is per photon (smaller scale as it is describing individual photons)