# Photoelectric Effect: Electron Flow Explained

• Leong
In summary, when the emitter is connected to the positive polarity of a battery, some high speed electrons are still able to reach the collector and therefore there is flow of current. The path of the electrons may not be linear, due to the kinetic energies of the electrons.
Leong
When the emitter is connected to the positive polarity of a battery, it is said that 'Some high speed electrons are still able to reach the collector and therefore there is flow of current.'

(1) What is the flow of electrons like in this case?

I thought electrons are supposed to flow from the negative polarity of the battery to the collector, to the emitter and finally to the positive polarity of the battery to produce a current.

(2) Why in this case, it is the other way round, yet it is said that there is a current?

In this case kinetic energies of the electrons are concerned, If the falling photons have enough energies to give high kinetic energies to electrons, electrons can move to the collector, but the path may not be a linear path

Hiranya Pasan said:
In this case kinetic energies of the electrons are concerned, If the falling photons have enough energies to give high kinetic energies to electrons, electrons can move to the collector, but the path may not be a linear path

Would you mind explaining how the electrons flow in the circuit & how the current flows in the circuit?

Leong said:
Would you mind explaining how the electrons flow in the circuit & how the current flows in the circuit?

Im not sure about this answer but I think when polarity reversed there are some FREE electrons come back to the emitter due to the Coulomb potential, I think this the the reason to the flowing current in the circuit, because it is not possible to flowing current through the collector in this case.

I'm trying to decipher what exactly is being asked here because some of the terms being used is a bit confusing.

Are you asking why, when you reverse-bias the cathode with respect to the anode, that there can still be a current flow in the "circuit"?

If this is the question, then this has more to do with the electronics. In a simple photoelectric experiment setup, one of the electrodes (either the cathode or the anode) has a "floating" potential. This allows for one to set a potential with respect to the other, but still allows for current to flow if charges either enter or leave it.

So for example, you may ground the cathode, and have the anode's potential to float. Then, you can reverse-bias the anode's potential, but any electrons that hits the anode are still flowing on that branch of the circuit, so current is registered. The built-in electronics allows that. The electrons that enter the anode do not make a closed loop back to the cathode. The circuit diagram that you see that often accompanies the photoelectric effect is highly simplified and often only a schematic representation of what is going on.

Zz.

davenn
The elementary approach to the photoelectric effect only discusses the maximum energy of photo electrons. It's more complicated than that because of the range of actual energies of those electrons. The potential of the Anode will affect how many of the electrons make it to the anode and how many fall back to the emitter. The (reverse)":stopping potential" is the minimum that will stop the flow completely.

## 1. What is the photoelectric effect?

The photoelectric effect is a phenomenon in which electrons are emitted from a material when it is exposed to light of a certain frequency or higher. This process is also known as photoemission.

## 2. How does the photoelectric effect explain electron flow?

The photoelectric effect explains electron flow by showing that electrons can be emitted from a material when it absorbs light energy. This energy can then be used to move the electrons, creating an electric current.

## 3. What causes the photoelectric effect?

The photoelectric effect is caused by the interaction between photons (particles of light) and electrons in a material. When a photon with enough energy is absorbed by an electron, it can cause the electron to be emitted from the material.

## 4. Why is the photoelectric effect important?

The photoelectric effect is important because it helps us understand the behavior of light and electrons, and has many practical applications. For example, it is used in solar panels to convert sunlight into electricity and in photodetectors to detect light.

## 5. What factors affect the photoelectric effect?

The photoelectric effect can be affected by several factors, such as the intensity and wavelength of the light, the type of material, and the work function (the minimum energy needed to remove an electron from the material). The photoelectric effect is also dependent on the number of electrons present in the material and their binding energy.

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