Answer:
Explanation:
The photoelectric effect consists of the emission of electrons (electric current) that occurs when light falls on a metal surface under certain conditions.
If the light is a stream of photons and each of them has energy, this energy is able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a kinetic energy.
<u>This is what Einstein proposed: </u>
Light behaves like a stream of particles called photons with an energy
(1)
Where:
is the Planck constant
is the frequency
Now, the frequency has an inverse relation with the wavelength :
(2)
Where is the speed of light in vacuum and
is the wavelength of the absorbed photons in the photoelectric effect.
Substituting (2) in (1):
(3)
So, the energy of the incident photon must be equal to the sum of the Work function
of the metal and the maximum kinetic energy
of the photoelectron:
(4)
Rewriting to find :
(5)
Where is the minimum amount of energy required to induce the photoemission of electrons from the surface of a metal, and its value depends on the metal:
(6)
Being the threshold wavelength (the minimum wavelength needed to initiate the photoelectric effect)
Substituting (3) and (6) in (5):
(7)
Substituting the known values:
>>>>>This is the maximum kinetic energy that ejected electrons must have when violet light illuminates the material