## Number of Photons

donnanguyen1d
Posts: 64
Joined: Fri Sep 29, 2017 7:04 am

### Number of Photons

What increases the number of photons? intensity?
Also, does increasing the intensity of incident light increase the number of electrons ejected? if so how? because I thought that during the experiment itself, increasing intensity did not eject an electron

Nancy Dinh 2J
Posts: 59
Joined: Fri Sep 29, 2017 7:07 am

### Re: Number of Photons

Yes, the greater the intensity, the more photons you'll have. Since theoretically, each photon ejects one electron given that it has enough energy, the number of electrons ejected will increase too.

This is based on the assumption that the photon already has enough energy to eject an electron. If the photon has an energy below the threshold energy, which was in the case of the experiment, then increasing the intensity (and therefore the number of photons) does nothing. You'll just have more ill-qualified photons trying to eject electrons.

Deap Bhandal L1 S1J
Posts: 77
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 2 times

### Re: Number of Photons

Another way to think of more photons is a higher amplitude. The wavelength determines whether the beam of light can eject an electron. Amplitude and wavelength can change independently from one another.

Jingyi Li 2C
Posts: 56
Joined: Fri Sep 29, 2017 7:06 am

### Re: Number of Photons

Yes, the number of photons increases as the intensity increases. This is the explanation for light with particle-like property.

If the energy of the photons reaches the threshold energy, then increasing the intensity of light will increase the number of electrons ejected since it is an one-photon-one-electron interaction. That is only the photons with energy greater than or equal to the threshold energy can interact with the electrons and emit them. In the case that increasing intensity cannot eject an electron is because the energy of each photon is lower than the threshold energy. So, it cannot eject an electron.

Michelle Lu 1F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 1 time

### Re: Number of Photons

An increase in intensity correlates with an increase in the number of photons. During the experiment, the reason why increasing the intensity didn't eject an electron explains why light has particle-like properties. Since photons each interact with only one electron each, even though there are many photons (meaning that the intensity is high), if each photon has less energy than the threshold energy, then no electrons will be ejected.