Kinetic energy of the photoelectrons

In summary, the largest kinetic energy of the photoelectrons generated by a beam of 200 nm ultraviolet light incident on a metal with a work function of 3.0 eV and applied potential of +1.0 V is 5.139*10^-19 J. To fully account for the potential, the kinetic energy must be modified accordingly.
  • #1
manaXmizery
3
0

Homework Statement


A beam of ultraviolet light with wavelength of 200 nm is incident on a metal whose work function is 3.0 eV. Note that this metal is applied with +1.0 V with respect to the ground. Determine the largest kinetic energy of the photoelectrons generated in this process.

Homework Equations


Kmax = hf - phi

Kmax = q*|V|

The Attempt at a Solution



I am not entirely sure what the statement about the +1.0 V implies and hence I simply used the formula
Kmax = hf - phi . Substituting the appropriate values gives Kmax = 5.139*10^-19 J . Am I on the correct path ?
 
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  • #2
You got the result in the absence of the applied potential. You must now modify the kinetic energy to take into account the potential.
 
  • #3
DrClaude said:
You got the result in the absence of the applied potential. You must now modify the kinetic energy to take into account the potential.
how do you take into account the potential?
 
  • #4
whatphysics said:
how do you take into account the potential?
By calculating its effect on the released photoelectron.
 

1. What is the definition of kinetic energy of photoelectrons?

The kinetic energy of photoelectrons refers to the energy that an electron gains when it is emitted from a material due to the absorption of a photon.

2. How is the kinetic energy of photoelectrons related to the frequency of the incident light?

The kinetic energy of photoelectrons is directly proportional to the frequency of the incident light. This is known as the photoelectric effect and was discovered by Albert Einstein.

3. Can the kinetic energy of photoelectrons be controlled?

Yes, the kinetic energy of photoelectrons can be controlled by adjusting the intensity of the incident light. A higher intensity of light will result in a higher kinetic energy of the emitted electrons.

4. What factors affect the kinetic energy of photoelectrons?

The kinetic energy of photoelectrons is affected by the frequency and intensity of the incident light, as well as the properties of the material from which the electrons are emitted, such as its work function and atomic structure.

5. How is the kinetic energy of photoelectrons measured?

The kinetic energy of photoelectrons can be measured using a device called a spectrometer, which measures the velocity of the emitted electrons and then calculates their kinetic energy using the formula KE = 1/2mv^2, where m is the mass of the electron and v is its velocity.

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