Photoelectric Effect and circuits

In summary, the threshold frequency for a metal can be calculated using the formula E = h.f, where E is the maximum kinetic energy of the ejected electron, h is Planck's constant, and f is the frequency of the incident light. The stopping voltage, which is the reverse voltage required to bring the current through the circuit to zero, is related to the work function of the metal according to the formula KE = e*V. This means that the stopping voltage can be used to determine the work function of the metal.
  • #1
Noir
27
0

Homework Statement


When 520nm light falls on a metal, the current through the circuit is brought to zero by a reverse voltage of 1.13V. What is the threshold frequency for this metal.


Homework Equations


E = h.f


The Attempt at a Solution


Using the above formula I get an threshold frequency of 2.72 x 10^14 Hz. Except here's my question, the reverse voltage doesn't have anything to do with the work function if it brings the current down to zero. Or does it, can someone please explain the process? I'm just confused by the term reverse voltage, or stopping voltage.

Thanks for any help :)
 
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  • #2
The maximum kinetic energy of the ejected electron is given by the stopping potential.
According to photoelectric effect
KE = hν - φ where φ is the work function.
 
  • #3
Thanks for your reply, but I'm still unclear on how the reverse voltage, or stopping voltage relates to the equarion.
 
  • #4
Kinetic energy = e*V, where e is the charge on electron and V is the stopping voltage.
 

1. What is the photoelectric effect?

The photoelectric effect is the phenomenon where electrons are emitted from a material when it is exposed to electromagnetic radiation, such as light.

2. How does the photoelectric effect work?

When light hits a material, it transfers energy to the electrons in the material. If the energy of the light is high enough, it can knock electrons out of the material, resulting in an electric current.

3. How is the photoelectric effect related to circuits?

The photoelectric effect is closely related to circuits because it involves the flow of electrons, which is the basis of electricity and circuits. In fact, the photoelectric effect is used in some electronic devices, such as photodiodes and solar cells.

4. What is a photoelectric circuit?

A photoelectric circuit is a circuit that utilizes the photoelectric effect to measure or detect light. It typically consists of a light source, a photosensitive material, and a circuit to measure the resulting current.

5. What are some practical applications of the photoelectric effect and circuits?

The photoelectric effect and circuits have many practical applications, such as in solar panels for generating electricity, in photography for capturing images, and in sensors for detecting light. They are also used in devices such as photocells, photomultipliers, and phototransistors.

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