Photoelectric Effect: Solving a Stopping Potential Problem

In summary, the conversation discusses a question related to the photoelectric effect and a graph representing stopping potential as a function of frequency of light. The person is trying to find the work function for a particular metal and has calculated it to be 5.17 eV, while the textbook lists the answer as 4.8 eV. They have also checked their calculations for other points and consistently get the same answer.
  • #1
nichelfish
1
0
Hey guys, thanks for any help in advance. I'm working through some exercises in University Physics 13th Edition and have an issue with a photoelectric effect question.

I'm given a graph that represents stopping potential as a function of frequency of light falling onto the surface (attached is a drawing, didn't want to post a direct pic incase it went against the rules). At a stopping potential of 0, the frequency is 1.25x10^15 Hz. As in this case hf=work function (and using h=6.626x10^-34 and e as 1.602x10^-19) I get, using parenthesis to try and make it clearer:

(1.25x10^15)x(6.626x10^-34) = 8.2825x10^-19 V

Converting to eV
(8.2825x10^-19) / (1.602x10^-19) = 5.17 eV.

The answer listed in the textbook gives 4.8eV. I've tried calculations for other points along the line (larger frequencies and stopping potentials) and get the same answer.

Anybody able to hint at as to where I may be going wrong?

Thanks in advance for any help.
 

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  • #2
Welcome to PF. Could you tell me what are you trying to find in particular? I'm guessing you're trying to find the work function for the particular metal. If that's the case, I don't see any error on your part.
 
  • #3
Other than your 1st eq. rt-hand-side should be J, not V, I see no error either.
 

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 or other electromagnetic radiation. This effect was first observed by Heinrich Hertz in 1887 and later explained by Albert Einstein in 1905.

2. How does the photoelectric effect work?

When light of a certain frequency (known as the threshold frequency) hits the surface of a material, it transfers energy to the electrons in that material. If the energy of the light is greater than the binding energy of the electrons, they will be emitted from the material. This is known as the photoelectric effect.

3. What is a stopping potential problem?

A stopping potential problem is a type of experiment used to measure the kinetic energy of electrons emitted from a material due to the photoelectric effect. It involves varying the voltage applied to a metal plate until the electrons are just barely stopped from reaching the other side, and then using this voltage to calculate the kinetic energy of the electrons.

4. How is a stopping potential problem solved?

To solve a stopping potential problem, the following steps are typically followed:1. Measure the threshold frequency of the material.2. Set up the experimental apparatus and vary the voltage until the electrons are just stopped.3. Record the stopping voltage.4. Use the stopping voltage and the threshold frequency to calculate the kinetic energy of the electrons.5. Repeat the experiment with different frequencies of light to gather more data points.6. Plot a graph of stopping voltage vs. frequency and determine the slope, which can be used to calculate Planck's constant.

5. What is the significance of solving a stopping potential problem?

Solving a stopping potential problem allows scientists to determine the kinetic energy of electrons emitted due to the photoelectric effect, which in turn allows them to calculate other important values such as Planck's constant. This experiment helped to provide evidence for the particle-like nature of light and played a crucial role in the development of quantum mechanics.

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