The photoelectric effect Summary GR 10 – 12 IEB
The Photoelectric Effect
The process that occurs when lights shines on a metal and electrons are ejected.
Significance of the photoelectric effect - it establishes the quantum theory and it
illustrates the particle nature of light.
Bodies Particles that make up the body Energy of the particle Formula
Energy called quanta
Light Photons E = hf
Work Function
Metal Electrons (Wo) Wo = hfo
Kinetic Energy
Photoelectrons Photoelectrons E k = ½ x m x v2
Light is shined on a metal which excites the electrons which come to the surface.
If the energy is more than the work function of the metal the electron will be
emitted from the surface of the metal and will produce kinetic energy.
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, The photoelectric effect Summary GR 10 – 12 IEB
Formulae:
1) v = λ . f
2) E= hf
hc
3) E=
λ
4) c= f λ
5) E = Wo + Ek (max)
6) hf = Wo + ½ mv2
7) Wo = hfo
Symbol Meaning Unit of measurement
v speed of ejected electron m.s-1
λ wavelength m
f frequency of light Hz
h Planck’s constant 6,63x 10-34 J.s
c speed of light 3 x 108 m.s-1
E energy of the photon J
Wo work function of a metal J
Ek (max) maximum kinetic energy of ejected electron J
fo threshold frequency Hz
m mass of electron 9,11 x 10-31 kg
Formulas:
m = milli = 10-3
μ= micro = 10-6
n = nano = 10-9
p = pico = 10-12
Other important values:
1 electron volt (eV) = 1,6 x10 -19 J
mass of electron = 9,11 x 10-31
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The Photoelectric Effect
The process that occurs when lights shines on a metal and electrons are ejected.
Significance of the photoelectric effect - it establishes the quantum theory and it
illustrates the particle nature of light.
Bodies Particles that make up the body Energy of the particle Formula
Energy called quanta
Light Photons E = hf
Work Function
Metal Electrons (Wo) Wo = hfo
Kinetic Energy
Photoelectrons Photoelectrons E k = ½ x m x v2
Light is shined on a metal which excites the electrons which come to the surface.
If the energy is more than the work function of the metal the electron will be
emitted from the surface of the metal and will produce kinetic energy.
1|Page
, The photoelectric effect Summary GR 10 – 12 IEB
Formulae:
1) v = λ . f
2) E= hf
hc
3) E=
λ
4) c= f λ
5) E = Wo + Ek (max)
6) hf = Wo + ½ mv2
7) Wo = hfo
Symbol Meaning Unit of measurement
v speed of ejected electron m.s-1
λ wavelength m
f frequency of light Hz
h Planck’s constant 6,63x 10-34 J.s
c speed of light 3 x 108 m.s-1
E energy of the photon J
Wo work function of a metal J
Ek (max) maximum kinetic energy of ejected electron J
fo threshold frequency Hz
m mass of electron 9,11 x 10-31 kg
Formulas:
m = milli = 10-3
μ= micro = 10-6
n = nano = 10-9
p = pico = 10-12
Other important values:
1 electron volt (eV) = 1,6 x10 -19 J
mass of electron = 9,11 x 10-31
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