Question
Discuss the Einstien's explanation for the photoelectric effect.
✓
Answer
→In 1905, Einstien gave a historical explanation of the photoelectric effect. For which he was awarded the Nobel prize in physics in 1921.
→Einstein accepted Max Planck's concept of radiation.
→According to this concept, the energy of radiation is not continuous. Radiation is composed of discrete units of energy, (Bundles of energy) These units of energy are called quanta or photons.
Each quantum (photon) has energy $E =h v$.
Where, $h=$ Planck's constant
$\begin{array}{l}
h=6.625 \times 10^{-34} J s \\
v=\text { Frequency of radiation }
\end{array}$
→When radiation is incident on a metal surface, the electrons in the metal interact with the quanta of the radiation. If the energy of quantum ( $h v$ ) is greater than the work function $\left(\phi_0\right)$ of a given metal, the electron absorbs this quantum. i.e. the full energy of the quantum ( $h v$ ) is absorbed and is emitted from the metal with a maximum kinetic energy $K _{\max }$.
Thus, $K _{ max }=h v-\phi_0$
→This equation is called Einstein's equation of photoelectric effect.
→If a photon interacts with an strongly bound electron than electron requires more energy to be ejected. So it is emitted with less energy than $K _{\max }$.
→Einstein accepted Max Planck's concept of radiation.
→According to this concept, the energy of radiation is not continuous. Radiation is composed of discrete units of energy, (Bundles of energy) These units of energy are called quanta or photons.
Each quantum (photon) has energy $E =h v$.
Where, $h=$ Planck's constant
$\begin{array}{l}
h=6.625 \times 10^{-34} J s \\
v=\text { Frequency of radiation }
\end{array}$
→When radiation is incident on a metal surface, the electrons in the metal interact with the quanta of the radiation. If the energy of quantum ( $h v$ ) is greater than the work function $\left(\phi_0\right)$ of a given metal, the electron absorbs this quantum. i.e. the full energy of the quantum ( $h v$ ) is absorbed and is emitted from the metal with a maximum kinetic energy $K _{\max }$.
Thus, $K _{ max }=h v-\phi_0$
→This equation is called Einstein's equation of photoelectric effect.
→If a photon interacts with an strongly bound electron than electron requires more energy to be ejected. So it is emitted with less energy than $K _{\max }$.
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