Wavelength, Frequency, and Intensity

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Sean Sugai 4E
Posts: 56
Joined: Wed Sep 11, 2019 12:17 am

Wavelength, Frequency, and Intensity

Postby Sean Sugai 4E » Sun Oct 13, 2019 9:03 pm

When discovering the photoelectric effect, why did short wavelengths (high frequencies) eject electrons but long wavelengths (low frequencies) couldn't? Also, why did the intensity of the light not matter?

Salma Fawzi 4G
Posts: 50
Joined: Wed Sep 18, 2019 12:20 am

Re: Wavelength, Frequency, and Intensity

Postby Salma Fawzi 4G » Sun Oct 13, 2019 9:22 pm

What is the relationship of wavelength and the intensity?

KSong_1J
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

Re: Wavelength, Frequency, and Intensity

Postby KSong_1J » Sun Oct 13, 2019 9:23 pm

Light is made up of photons and the photon’s energy is dependent on its wavelength; longer wavelengths of light have less energy than shorter wavelengths, which is why the shorter wavelengths are able to eject the electrons (since they have more energy and you need to reach a certain threshold to eject the electron). The intensity doesn’t matter because it has to do with the frequency of the light.

Snigdha Uppu 1G
Posts: 49
Joined: Sat Sep 07, 2019 12:15 am

Re: Wavelength, Frequency, and Intensity

Postby Snigdha Uppu 1G » Sun Oct 13, 2019 9:25 pm

wavelength and frequency are inversely related so when wavelength increases, frequency decreases, which means there is less intensity coming from the wave, so less energy.

Snigdha Uppu 1G
Posts: 49
Joined: Sat Sep 07, 2019 12:15 am

Re: Wavelength, Frequency, and Intensity

Postby Snigdha Uppu 1G » Sun Oct 13, 2019 9:27 pm

intensity is the number of photons emitted and frequency is the number of waves during a certain period

Haley Pham 4I
Posts: 51
Joined: Fri Aug 09, 2019 12:16 am

Re: Wavelength, Frequency, and Intensity

Postby Haley Pham 4I » Sun Oct 13, 2019 9:31 pm

A photon must have a wavelength that is lower than the threshold wavelength to have the required energy to eject electrons. According to the equation E = hv = hc/λ (λ being wavelength), having a long wavelength would decrease the energy needed to eject the electrons. Thus, having a shorter wavelength would produce the energy required to eject electrons.

Kaylee Clarke 1G
Posts: 103
Joined: Fri Aug 30, 2019 12:15 am

Re: Wavelength, Frequency, and Intensity

Postby Kaylee Clarke 1G » Sun Oct 13, 2019 9:40 pm

Shorter wavelengths have higher frequencies, which means more energy to eject electron.. which is why the electrons are reactive to short wavelengths. And, the wavelength is not effected by the intensity of the light source, so there will not be more energy in the photons.

TheresaDsilva4A
Posts: 53
Joined: Thu Jul 25, 2019 12:17 am

Re: Wavelength, Frequency, and Intensity

Postby TheresaDsilva4A » Sun Oct 13, 2019 10:00 pm

Is there a particular equation relating intensity to other variables? I'm still a little confused why intensity plays no role at all in the photoelectric effect. Thanks!


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