The Ultraviolet Catastrophe (7.1.4) Flashcards
• Classical physics was unable to predict the intensities of light given off by heated objects.
• Classical physics was unable to predict the intensities of light given off by heated objects.
• Max Planck theorized in 1900 that energy can only be absorbed in discrete packets related to the frequency of an oscillator.
• Max Planck theorized in 1900 that energy can only be absorbed in discrete packets related to the frequency of an oscillator.
When an object is heated, light is emitted. This is
called incandescence. The intensities of light
emitted at different wavelengths (different colors)
depend on the temperature of the object. For
instance, a stove burner changes from red to
orange as it becomes hotter.
Incandescence is caused by vibrations of the atoms
making up the heated object. As the object is
heated, the atoms within it begin to vibrate. These
vibrations set up an electromagnetic wave—light.
Different frequencies of vibration lead to different
frequencies of light.
Using classical mechanics, physicists were able to
predict the intensities of light emitted at low
frequencies (long wavelengths) for a given
temperature using this model. However, the
predictions greatly overestimated the light given off
at short wavelengths, specifically in the ultraviolet
region. Since nothing in classical physics could
explain the observed intensities, this problem was
named the ultraviolet catastrophe.
Max Planck theorized in 1900 that energy can only
be absorbed in discrete packets related to the
frequency of an oscillator—that energy is
quantized. This is expressed mathematically as
Eosc = n • h • ν, where ν is the frequency of the
oscillator, h is Planck’s constant, and n is an
integer.
Using Planck’s theory, high-frequency oscillators
require larger packets of energy than low-frequency
oscillators. This means that high-frequency
oscillators are not able to absorb as much energy as
previously predicted, and therefore less highfrequency
light is given off.
This correction causes the predicted intensities to
match the observed intensities for any frequency of
light. The idea of quantized energy led to a
revolution in the way chemists and physicists
thought about the world.
When an object is heated, light is emitted. This is
called incandescence. The intensities of light
emitted at different wavelengths (different colors)
depend on the temperature of the object. For
instance, a stove burner changes from red to
orange as it becomes hotter.
Incandescence is caused by vibrations of the atoms
making up the heated object. As the object is
heated, the atoms within it begin to vibrate. These
vibrations set up an electromagnetic wave—light.
Different frequencies of vibration lead to different
frequencies of light.
Using classical mechanics, physicists were able to
predict the intensities of light emitted at low
frequencies (long wavelengths) for a given
temperature using this model. However, the
predictions greatly overestimated the light given off
at short wavelengths, specifically in the ultraviolet
region. Since nothing in classical physics could
explain the observed intensities, this problem was
named the ultraviolet catastrophe.
Max Planck theorized in 1900 that energy can only
be absorbed in discrete packets related to the
frequency of an oscillator—that energy is
quantized. This is expressed mathematically as
Eosc = n • h • ν, where ν is the frequency of the
oscillator, h is Planck’s constant, and n is an
integer.
Using Planck’s theory, high-frequency oscillators
require larger packets of energy than low-frequency
oscillators. This means that high-frequency
oscillators are not able to absorb as much energy as
previously predicted, and therefore less highfrequency
light is given off.
This correction causes the predicted intensities to
match the observed intensities for any frequency of
light. The idea of quantized energy led to a
revolution in the way chemists and physicists
thought about the world.
