How to calculate threshold frequency of a metal

In summary, to determine the threshold frequency of a metal with a work function of 7V, you would use the equation f=W/h where W is the work function and h is Planck's constant. However, if the work function is expressed in volts, it needs to be converted to joules per electron rather than joules per coulomb. This is because each photon only liberates one electron, so the conversion is necessary for accurate calculation.
  • #1
Justin Hawk
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0

Homework Statement


Determine the threshold frequency of a metal with a work function of 7V


Homework Equations


Threshold frequency 'f'=W/h where w=work function, h=planck's constant


The Attempt at a Solution


This is such an easy question, but I am hung up on how to treat a work function that is expressed in volts seeming as the equation used to calculate the frequency requires it to be in joules I believe. I understand that volts can be expressed as joules per coulomb, but what would I do about the coulombs then?
 
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  • #2
With one photon liberating one electron, you should convert from Joules per coulomb, to Joules per electron.
 

1. What is threshold frequency of a metal?

The threshold frequency of a metal is the minimum frequency of light required to eject an electron from the surface of the metal. It is also known as the minimum excitation frequency or cutoff frequency.

2. How do you calculate the threshold frequency of a metal?

The threshold frequency of a metal can be calculated using the equation: f0 = (ϕ/h), where f0 is the threshold frequency, ϕ is the work function of the metal, and h is Planck's constant.

3. What is the significance of the threshold frequency of a metal?

The threshold frequency of a metal is significant because it is a characteristic property of the metal and can be used to identify the type of metal. It also helps in understanding the behavior of electrons in metals and their interaction with light.

4. How does the threshold frequency of a metal affect the photoelectric effect?

The threshold frequency of a metal is directly related to the energy required to eject an electron from its surface. If the frequency of incident light is lower than the threshold frequency, no electrons will be ejected, regardless of the intensity of the light. This is known as the cutoff effect and is a key aspect of the photoelectric effect.

5. Can the threshold frequency of a metal be changed?

The threshold frequency of a metal is a characteristic property of the metal and cannot be changed. However, the work function of a metal can be changed by altering its surface, such as through oxidation or coating with a thin film. This will in turn affect the threshold frequency of the metal.

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