The
Photoelectric
Effect
Lenard 1902 · Einstein 1905 · Millikan 1916
E = hf · K
max
= hf − φ
Metal surface under illumination
—
Controls
Source & target
Frequency
f
—
Intensity
photons / s
—
Cathode metal
φ
Photon energy
—
Work function φ
—
Max kinetic energy
—
Threshold f₀
—
Stopping voltage
—
Photocurrent
—
K
max
vs frequency
slope = h
Photocurrent vs intensity
at fixed f
❚❚
Time
0.00 fs