Photoelectric Effect and ozone layer

In summary, the conversation discusses the possibility of direct sunlight producing photoelectrons from a penny, given that the ozone layer blocks most of the solar radiation with wavelengths shorter than 320nm. It is mentioned that pennies are made of zinc coated with copper, and the work function of copper is 4.7eV. The conversation also includes calculations to determine the minimum kinetic energy needed for electrons to escape from copper, and the energy per photon at a wavelength of 200nm. However, it is noted that the reasoning used is incorrect and needs to be revised.
  • #1
fireandwater
3
0
Hi. I hope someone can help. Here is the problem:

[Pennies are made of zinc coated with copper. Copper has a work function of 4.7eV. The ozone layer blocks nearly all solar radiation with wavelength shorter than 320nm, but a very small amount of 200nm light still manages to reach the Earth's surface. Can direct sunlight produce photoelectrons from a penny?]

I converted the 4.7eV into joules: 4.7eV * 1.602e-19J = 7.529e-19J
I found the minimum kinetic energy needed to for the electrons to escape from the copper:
KE = e * V_o => 1.602e-19 * 7.529e-19 = 1.206e-37J

I'm thinking that I need to use the 200nm to find out whether the kinetic energy I calculated will be produced by the sunlight, but I don't see how to do that.
 
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  • #2
Your reasoning is incorrect. KE = E - W (E is energy per photon, W is work function, KE is max kinetic energy of photoelectron).

Stay in eV, it's easier. Use 4.14 x 10^-15 eVs as h.

Energy per photon is hf =hc/wavelength.

How much energy in a 200 nm photon?
 
Last edited:
  • #3
Thank you!
 

Related to Photoelectric Effect and ozone layer

1. What is the photoelectric effect?

The photoelectric effect is a phenomenon in which electrons are emitted from a material when it is exposed to light of a certain frequency. This effect was first described by Albert Einstein in 1905 and has important applications in solar panels and photodetectors.

2. How does the photoelectric effect contribute to the formation of the ozone layer?

The photoelectric effect plays a crucial role in the formation of the ozone layer. UV radiation from the sun strikes oxygen molecules in the stratosphere, causing them to break apart into single oxygen atoms. These atoms then combine with other oxygen molecules to form ozone, which absorbs harmful UV radiation and protects the Earth's surface.

3. What is the relationship between the photoelectric effect and the ozone hole?

The photoelectric effect is not directly related to the formation of the ozone hole. The ozone hole is caused by human-made chemicals, such as chlorofluorocarbons (CFCs), which deplete the ozone layer by reacting with ozone molecules. However, the photoelectric effect is indirectly related to the ozone hole as it contributes to the formation of ozone, which helps to repair the ozone layer.

4. Can the photoelectric effect be used to measure the thickness of the ozone layer?

Yes, the photoelectric effect can be used to measure the thickness of the ozone layer. By measuring the intensity of light before and after it passes through the atmosphere, scientists can determine the amount of ozone present and thus calculate the thickness of the ozone layer.

5. How does the photoelectric effect impact our daily lives?

The photoelectric effect has a significant impact on our daily lives. It is the underlying principle behind solar panels, which convert sunlight into electricity. It is also used in photodetectors, such as digital cameras and smoke detectors. Additionally, the photoelectric effect is important in understanding the behavior of light and electrons, leading to advancements in technology and scientific research.

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