Photoelectric Effect
Overview of photoelectric effect & equations
- Created by: akelly_3102
- Created on: 03-05-18 17:32
View mindmap
- Photoelectric Effect
- EM photons allow electrons to be emitted
- Electrons are emitted as long as the light is above the threshold frequency
- High frequency = electrons emit quickly
- Low frequency = electrons emit more slowly
- Electrons are emitted as long as the light is above the threshold frequency
- Ek is independent of light intesity
- Increasing the intensity only increases the amount of photons per second on the area
- Because electrons can only absorb one photon of light at a time
- Increasing the intensity only increases the amount of photons per second on the area
- Work function
- The energy required to break the bonds that hold the electron to the metal
- If energy gained from photon > work function then electrons are emitted
- If energy gained from photon < work function then electrons are not emitted
- f0 = threshold frequency
- Electrons are emitted as long as the light is above the threshold frequency
- High frequency = electrons emit quickly
- Low frequency = electrons emit more slowly
- Electrons are emitted as long as the light is above the threshold frequency
- theta = work function
- h = Planck Constant
- The energy required to break the bonds that hold the electron to the metal
- Max kinetic energy
- Energy transferred from EM radiation to electron is the energy it absorbs from one photon
- Photon = hf
- Ek the electron will have when it leaves the metal = hf - other energy losses
- Minimum Ek is the work function energy
- Therefore, max Ek = hf - theta
- Minimum Ek is the work function energy
- Rearrange to give photoelectric equation
- hf = theta + max Ek
- Ek = 1/2mv^2 is max energy a photoelectron can have
- This can be used to write the photoelectric equation as: hf = theta + 1/2mv^2
- hf = theta + max Ek
- Ek = 1/2mv^2 is max energy a photoelectron can have
- This can be used to write the photoelectric equation as: hf = theta + 1/2mv^2
- This can be used to write the photoelectric equation as: hf = theta + 1/2mv^2
- Ek = 1/2mv^2 is max energy a photoelectron can have
- hf = theta + max Ek
- This can be used to write the photoelectric equation as: hf = theta + 1/2mv^2
- Ek = 1/2mv^2 is max energy a photoelectron can have
- hf = theta + max Ek
- Energy transferred from EM radiation to electron is the energy it absorbs from one photon
- Stopping potential
- Photoelectrons can be made to lose their energy by doing work against an applied potential difference
- Stopping potential = pd needed to stop the fastest electrons travelling with max Ek
- eVs = Ek(max)
- where eVs = charge on electron * stopping potential in V
- eVs = Ek(max)
- EM photons allow electrons to be emitted
Comments
No comments have yet been made