Photoelectric effect threshold

In summary, the stopping potential for a 1cm thick surface illuminated with light of wavelength lambda is V, and when illuminated with light of wavelength 2lambda, it is V/3. The threshold wavelength for the surface can be found by using the equation KE(Max) = hc/lambda, where KE(Max) is the stopping potential and hc/lambda is the energy of the photons. The role of the thickness of the surface is simply to ensure that it is of suitable thickness for our purposes. It is also important to assume a non-zero work function, as it is fixed at some value. The textbook may provide the correct answer for the threshold wavelength.
  • #1
Nairabhi
3
0
When a cm thick surface is illuminated with light of wavelength lambda,the stopping potential is V. When the same surface is illuminated by light of wavelength 2lambda , the stopping potential is V/3.The threshold wavelength for the surface is ?

Homework Equations

The Attempt at a Solution

 
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  • #2
Did you try to do this problem yourself?
 
  • #3
Matterwave said:
Did you try to do this problem yourself?
Yes i tried but i am unable to solve it.
 
  • #4
Nairabhi said:
Yes i tried but i am unable to solve it.

Hi Nairabhi. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

What equations do you have that you'll use here?
 
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  • #5
NascentOxygen said:
Hi Nairabhi. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

What equations do you have that you'll use here?
See according to Einstein equation KE(Max)= Energy of photons - work function of surface, but since work function is not given i have assumed it
to be 0. And energy of photons is equal to hc/lamda and this energy is equal to KE(Max) or the stopping potential so using these equations and i am trying to find a relation between them and find the threshold wavelength .However i don't understand what role does the thickness of surface plays which is 1cm ?
 
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  • #6
You should assume work function is non-zero, and is fixed at some value.

That material thickness may simply mean "of suitable thickness" for our purposes.

Does the textbook give the correct answer?
 

1. What is the photoelectric effect threshold?

The photoelectric effect threshold is the minimum amount of energy required to remove an electron from a metal surface. This energy is known as the work function and is specific to each type of metal.

2. How does the photoelectric effect threshold relate to the frequency of light?

The photoelectric effect threshold is directly related to the frequency of light. If the frequency of light is below the threshold, no electrons will be emitted from the metal surface. If the frequency is above the threshold, electrons will be emitted with greater kinetic energy as the frequency increases.

3. What is the significance of the photoelectric effect threshold?

The photoelectric effect threshold was a key discovery in understanding the nature of light and electrons. It provided evidence for the particle-like behavior of light and helped to develop the concept of photons. It also led to the development of modern technologies such as solar panels and photoelectric cells.

4. How is the photoelectric effect threshold affected by the intensity of light?

The intensity of light does not affect the photoelectric effect threshold. The threshold is only dependent on the frequency of light, not its intensity. However, increasing the intensity of light will result in a higher number of electrons being emitted from the metal surface once the threshold is reached.

5. Can the photoelectric effect threshold be changed?

The photoelectric effect threshold is a fundamental property of each type of metal and cannot be changed. However, the threshold can be altered by changing the type of metal used or by applying an external electric field to the metal surface.

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