Intensity vs. Frequency

[Javier Perez M 1H]

What is intensity and what is frequency?
As far as I know frequency is just the amount of cycles per an amount of time or waves. However, what exactly is intensity?

[Evie Li_1H]

Increasing the intensity of light would just mean sending a greater number of photons. That's why increasing the intensity of light won't eject electrons if that frequency of light is unable to do so. EACH electron needs to be able to have a high enough frequency to eject an electron. Increasing the intensity is only sending more of those photons that are unable to eject electrons, so it wouldn't change anything.

[Isaac Wen]

For a wave, the intensity is the amplitude (how tall the crest is). Frequency, as you described is the number of cycles per second. For a photon/particle, the intensity is the number of photons passing an area in a certain amount of time. Normally, increasing the intensity (amplitude) of a wave would increase energy, but scientists found that this was not the case in the photoelectric experiment. That's why they concluded that light could also be a particle, where an increase in intensity would only be an increase in the number of photons present.

[Ariel Guan 1H]

Intensity corresponds with the amount of photons in a particle, meaning high intensity= more photons and lower intensity = less photons. Intensity also is the amplitude of the wave in a wave model. In terms of the photoelectric effect, intensity wouldn't change the energy of the photons, which was the unexpected discovery.

[Sam_Marasigan_3D]

The intensity of light is basically the number of photons falling on a certain area.

[FionaHunter21]

So just to clarify: an increase in frequency increases the energy of the wave and the number of photons, but not the energy per photon? And this is what the photoelectric effect is? That the waves have particle like properties where only one photon interacts with an electron, and therefore changing the number would not help to displace an electron?

[Kelly Ha 1K]

So just to clarify: an increase in frequency increases the energy of the wave and the number of photons, but not the energy per photon? And this is what the photoelectric effect is? That the waves have particle like properties where only one photon interacts with an electron, and therefore changing the number would not help to displace an electron?

I believe it is just the opposite. An increase in intensity would increase the number of photons, and an increase in frequency would increase the energy per photon and thus correspond to an increased kinetic energy of the photoelectrons being emitted. It is correct that one photon interacts with one electron, but this concept of the photoelectric effect actually shows that light acts as a particle, not only as a wave.
In the photoelectric effect experiment, it showed that you needed to increase the frequency of the light source in order to increase the energy per photon and then be able eject the electrons, not just increase the intensity. If light were to act only as a wave, then increasing intensity should eject electrons but it was discovered that that didn't occur. Light is therefore quantized as photons (packets of energy) where one photon interacts with one electron.

[Charmaine Ng 2D]

You're right about the frequency! It's the cycles that pass through within a given time, and is also indicative of the energy, since E=hv. Energy and frequency are proportional, so the higher the frequency, the more energy. Meanwhile, intensity refers to the amount of photons in a light beam, not how much energy is in each photon.

[derickngo3d]

Intensity of light is the number of photons. Frequency relates to a single photon, and whether it can eject electrons off of metal.

[Chris_Butler_1A]

You're right about the frequency! It's the cycles that pass through within a given time, and is also indicative of the energy, since E=hv. Energy and frequency are proportional, so the higher the frequency, the more energy. Meanwhile, intensity refers to the amount of photons in a light beam, not how much energy is in each photon.

And just to make sure, the frequency of a wave is defined as the number of hills, troughs, or any other starting point of a wave passes in a second, right? Thus why we can say that the frequency is in Hertz?

[Vanshika Bhushan 1A]

Frequency is related to photon's energy where E = hν , E is energy, h is Planck's constant and ν is frequency. In particle nature, intensity is related to number of photons in the radiation. Intensity is power per unit area and power is energy per time.

[Ivy Tan 1E]

Hi!
I think intensity corresponds to the amplitude of the wave and frequency is the number of wave cycles per second. This is why in the atomic spectra experiment, increasing the intensity of the light would only increase the amplitude of the wave, not its energy. Increasing the frequency of a wave would increase its energy, thus increasing the energy per photon. Hope this was helpful!!

[Mackenzie Stockton 2H]

For a particle-model, increasing intensity means increasing the amplitude, which increases the energy. This refers to increasing the intensity (brightness) of the light

For a wave-like model, increasing intensity does not increase the energy because the EMR is acting like a particle and not a wave. Increasing intensity in this case still refers to increasing the brightness of light, but since light is acting like a wave, it does not increase energy. To increase the energy when light is acting like a wave, you must increase the frequency, as E=hv

[Emilie_Paltrinieri_1K]

So what was the new equation that they found after doing the experiment of the photoelectric effect?

[Scot Widjaja Dis 1J]

Frequency is a measure of the number of times a wave goes through its cycle per unit of time (seconds). Intensity is a measure of how large or how high the waves are. In other words, it is the amplitude of the waves and the larger the intensity, the higher the number of photons.

[Sabrina Galvan 3J]

So what was the new equation that they found after doing the experiment of the photoelectric effect?

They found that the energy of a photon is proportional to planks constant and frequency
Ephoton=(h)(v)

[Chudi Onyedika 3A]

When increasing the intensity of light, the number of photons are increased.

[Keshav Patel 14B 2B]

Frequency is the amount of waves that are being sent in a period of time. Intensity is the light that can increase but the photons rendered in light can increase which is how intensity increases.

[Brian Nguyen 2I]

Intensity relates to amount of photons, whereas frequency relates to the quality of a photon. Frequency is the number of cycles per second.

[Kyle Dizon 3A]

The intensity is related to the number of photons of the light.

[Simran Bains 2C]

The intensity has to do with the amount of photons that are in the beam of lights, whereas the frequency of the light is the amount of times that the wave repeats every second.

[Kainalu Puu-Robinson]

When determining wave energy, do we just look at the frequency of a wave or at the amplitude as well. This was one of the Sapling questions and by the options given it was clear to tell but I'm not actually sure what the correct way to go about it is.

[Lillian]

For something like a photon, the intensity would refer to the the number of photons sent at a target or in a certain direction. The frequency would refer to how many crests or troughs pass through a certain point in a wave. The amplitude, just in case, refers to the height of the crest or trough.