The document discusses the photoelectric effect, which involves incoming photons striking a metal plate and emitting electrons. It occurred in 1887/1905 and provided evidence for the particle nature of electromagnetic radiation. The photoelectric effect showed that the kinetic energy of emitted electrons depends on the frequency of photons striking the metal plate, not the intensity, supporting Einstein's hypothesis that electromagnetic radiation consists of discrete photon particles with energy proportional to their frequency.

1. Incoming photons Outcoming electrons
metal plate
Photoelectric effect
1887/1905
The particle nature of electromagnetic radiation
H. Hertz (1857-1894) A. Einstein (1879-1955)
From the Udemy online course: https://www.udemy.com/quantum-physics/?couponCode=SLIDESHCOUPON

2. Incoming photons Outcoming electrons
metal plate
Photoelectric effect
1887/1905
The particle nature of electromagnetic radiation
H. Hertz (1857-1894) A. Einstein (1879-1955)

3. Visible spectrum
Photoelectric effect
Ekin
𝝀 𝟎 =
𝒄
𝝂 𝟎
Metallic surface
𝝓
Electron‘s kin. energy = photon‘s energy – work function
Ekin= 𝐡𝛎 − 𝝓
𝝂 𝟎
𝝂 [𝒙 𝟏𝟎 𝟏𝟒
Hz]
𝝀 𝟎 =
𝒄
𝝂 𝟎
𝝂 𝟎

4. Visible spectrum
Photoelectric effect
Ekin
𝝀 𝟎 =
𝒄
𝝂 𝟎𝝓
Electron‘s kin. energy = photon‘s energy – work function
Ekin= 𝐡𝛎 − 𝝓
𝝂 𝟎
𝝂 [𝒙 𝟏𝟎 𝟏𝟒
Hz]
Outcoming electrons
metal plate
Incoming photons

5. Nobel prize in 1921 “For his services to theoretical physics, and
especially for his discovery of the law of the photoelectric effect"
𝛾
The „photon“