# What is the work function of the photoelectric material?

• ikihi
In summary, we can calculate the work function of a photoelectric material by subtracting the energy of a photon with a given momentum from the kinetic energy of the electron, as shown in the figure and equations provided. The resulting value is 2.36 eV.
ikihi

## Homework Statement

Photons with momentum p= 7.88 x 10-18 strike a photoelectric material which is in the configuration shown in the figure. The cutoff voltage is measured to be Vstop= 1.75 V. What is the work function of the photoelectric material?

## Homework Equations

p = Ephoton / c
E0 = (c ⋅ p) - (Vstop ⋅ e)

## The Attempt at a Solution

E0 = (3.00 x 108 m/s)(7.88 x 10-18 (ev ⋅ s)/nm) - (1.75 V ⋅ 1.602 x 10-19 J) = 2.36 eV

#### Attachments

• setup.PNG
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Last edited:
you should convert the speed of light to nm/s to match the momentum unit (ev.s/nm)

ikihi
patric44 said:
you should convert the speed of light to nm/s to match the momentum unit (ev.s/nm)

Thanks for catching that error. The new answer I got is 2.36 eV

ikihi said:
Thanks for catching that error. The new answer I got is 2.36 eV
you are welcome.

thats still the energy of the photon
subtract that from the ke

## 1. What is the definition of work function in terms of a photoelectric material?

The work function of a photoelectric material is the minimum amount of energy required for an electron to be emitted from the surface of the material, also known as the threshold energy. It is a characteristic property of the material and is measured in electron volts (eV).

## 2. How is the work function of a photoelectric material determined?

The work function of a photoelectric material can be determined experimentally by using the photoelectric effect. This involves shining a beam of light onto the material and measuring the energy of the emitted electrons. The minimum energy required to emit electrons is equal to the work function of the material.

## 3. What factors affect the work function of a photoelectric material?

The work function of a photoelectric material can be affected by several factors, including the type of material, its atomic structure, and the intensity and frequency of the incident light. Generally, materials with higher atomic numbers and tighter binding energies have higher work functions.

## 4. How does the work function of a photoelectric material relate to the kinetic energy of emitted electrons?

According to the photoelectric effect, the kinetic energy of emitted electrons is directly proportional to the frequency of the incident light and inversely proportional to the work function of the material. This means that the higher the work function, the more energy is required for electrons to be emitted and the lower their kinetic energy will be.

## 5. Can the work function of a photoelectric material be changed?

Yes, the work function of a photoelectric material can be changed by altering the material's surface, such as by introducing a thin layer of a different material. This changes the material's electronic structure and can lower the work function, making it easier for electrons to be emitted.

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