Define stopping potential

The minimum energy needed to eject an electron from a metal is known as the work function of the metal. Work function is different for different metals. A photon having an energy at least equal to the work function can eject electron from the metal, frequency of such a photon whose energy is just equal to the work function is called Threshold Frequency. Work Function ; W = h ν o ; Where , ν o is Threshold Frequency Electrons are, therefore, emitted only if the frequency of the photon is greater than the threshold frequency. Kinetic energy of photoelectron : In practice, the emitted photo electrons have a range of kinetic energies. Suppose that, the energy of an incident photon is E and the work function of the metal is W. The maximum K.E. that the photoelectron can have is given by the expression T max = E − W If the frequency of the photon is ν and threshold frequency for the metal is ν o, then T max = h(ν − ν o) For ν < ν o , electron is not ejected. We can draw two conclusions: (i) The kinetic energy of the ejected electron depends linearly on the frequency of the photon. (ii) The number of Photo electrons ejected per unit time depends on the intensity of the light, frequency of light being kept constant The experimental arrangement for observing the photoelectric effect is shown in the following figure. All the ejected electrons are not able to leave the surface and hence are not able to reach the anode. With an increase in potential difference across the tube, the num...

Hint: Photoelectric effect is the ejection of an electron when electromagnetic radiation or photon is absorbed by the electron. For the electron to be ejected the absorbed must have a frequency higher than the threshold frequency of the material. Threshold Energy is the minimum energy required by an electron for ejection from the metal surface, it is also called the photoelectric work function. Complete step-by-step answer: When light or a photon with optimum energy hits a metal surface, the surface of the metal ejects electrons by absorbing the photon of optimum energy. This effect is called the Photoelectric Effect. For the electron to be ejected the photon must have energy equal to or more than the threshold energy of metal. The ejected electron is called a Photoelectron. The extra energy of the photon, that is the energy it has on top of the threshold energy, gets transferred to the photoelectron in the form of Kinetic Energy. In the Photoelectric Experiment, light or photon is directed towards a metal plate, called the emitter, and if the photons have energy equal to or more than the threshold energy of metal, the photoelectron is ejected. The ejected electron, with Kinetic Energy from the photon, then moves to a second metal plate, called the collector, that is kept across the emitter plate. This movement of photoelectrons from emitter to the collector causes a current called the Photoelectric current. As we already know that electrons move from lower potential to hi...

in photoelectric experiments we are always interested in finding two things one is counting the number of electrons coming out per second something that we discussed in our previous video and the second which we'll discuss in this video is calculating or measuring the maximum kinetic energy of the electrons so the question is how do you find what is the maximum energy with which these electrons are coming out i find it even fascinating that we can even perform experiments to do that now just to quickly recap we've already seen the experimental setup we used to count the number of electrons emitted per second the whole idea was the number of electrons collected per second must be a direct indicator of the current the current directly indicates how many electrons were collected per second but that did not necessarily mean the may not necessarily be the same as the number emitted per second because some electrons can be lost not all electrons will be collected and so then we attached a battery to ensure the collector can suck all the electrons and we realize that as we increase the voltage this current starts increasing and eventually it maxes out when the current has reached maximum that's when i know for sure that all the emitted electrons almost all the limited electrons must be getting collected because the current is not increasing anymore and that current and we draw a graph we draw a graph of the voltage of the collector versus this current the current over here and we...

Table of Contents • • • • • • • • What is stopping potential and its formula? At some voltage, called the “stopping potential,” no electrons reach the collector, and there will be no current. When the voltage equals the stopping potential, we know that the KE fo the ejected electrons just equals the potential energy at the collector or… KE = PE hf – φ = qV. This equation is very useful. What is stopping potential in photoelectric field? The potential at which this occurs is called the stopping potential . It is a measure of the maximum kinetic energy of the electrons emitted as a result of the photoelectric effect. What is stopping potential and threshold frequency? Stopping potential or the cut-off potential is the minimum value of negative potential at anode which just stops the photo electric current. Threshold frequency is the minimum frequency of light below which photoelectric effect does not take place. What is stopping potential in simple language? Answer: Stopping potential or cut-off potential is defined as the required potential for stopping the removal of an electron from a metal surface when the incident light energy is greater than the work potential of the metal on which the incident light is focused. Does stopping potential depends on frequency? The stopping potential does not depend on the intensity nor the number of incident photons but the stopping potential depends on the frequency of the incident light, the higher the frequency of the incident light hi...

I am reading an introduction article for photoelectric effect. It is said that the variable potential was tuned until no single one photoelectron can reach the electron collection plate. But if we look at the current-voltage diagram, the stopping potential is negative. I have a hard time to understand why this potential is negative. As I learn from the text, the potential energy an electron experiences should be $-eV$, if voltage difference $V$ is negative, the potential energy should be positive. If the potential energy that an electron has is positive, should be electron move by itself spontaneously? So as my understanding, the more negative voltage difference there is, the more positive potential energy will be, so the electron should move towards the collection plate. So why there is stopping potential and why any voltage difference less than the stopping potential doesn't emit any electron? For photon energies above what is needed to kick out photoelectons, the electron is departing the surface with some excess kinetic energy (or else you'd never detect them since they'd go nowhere). A negatively charged electron is repelled from a negatively charged plate, and to climb 'up' that potential to reach the plate requires $e \times V$ energy (conveniently given in eV!). So, a positively charge plate will attract all emitted electrons, regardless of their kinetic energy upon leaving the solid. A neutral plate will pick up all electrons that headed towards it (and didn't sca...

• The minimum retarding potential means the negative potential of the anode of a photoelectric tube for which photoelectric current stops or becomes zero is called stopping potential. • Stopping potential does not depend on the intensity of incident light. On increasing intensity, the value of saturated current increases, whereas the stopping potential remains unchanged. • For a given intensity of radiation, the stopping potential depends on the frequency. Higher the frequency of incident light higher the value of stopping potential and vice-versa.