Light
Wave or Particle?
Evidence
Wave Properties
Particle Properties
Interference of Light
When two light waves hit they _______________________________ each other.
While they occupy the same space the waves _______ amplitudes and frequencies
to produce a different wave. This is called _______________________.
If two _________ hit they bounce off each other. They don’t interfere like waves.
Refraction & Dispersion of Light
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When light enters glass it _________.
This is called ____________
How much light refracts depends on
the type of _____ and the ____ of light.
A particle could refract, wave theory
works better.
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When _________ light enters glass the
different frequencies bend differently.
This causes the light to split into the
____________.
This is called ______________.
Particles wouldn’t display dispersion.
The Doppler Effect for Light
When a light source is moving the frequency of light it emits changes due to this
_____________.
A particle doesn’t do this, only a _____________.
Diffraction of Light
You get a _________________, called a _______________________ pattern.
Basically the light __________ as it _________ the slit causing an alternating
series of constructive and destructive interference.
A particle wouldn’t do this.
If I fire this laser through a
small slit, what will I see on the
wall when it hits?
The Photoelectric Effect
• When light hits certain metals it causes the metal to eject ______________.
• Treating light as a wave tells us that the __________ the light, the more electrons get
ejected or the electrons get ejected at a ________________.
• This would be true if it wasn’t__________!!!
• It turns out the ______________ of the light is what determines whether or not
electrons are ____________ from the metal.
• This suggests that light travels in _________ or packets called _______ which behave
like particles.
The Ultraviolet Catastrophe
• A blackbody radiator absorbs all
electromagnetic radiation that hits
it and emits its own electromagnetic
radiation based on its ___________.
• Wave theories predict that the
wavelengths of electromagnetic
waves a blackbody will emit should
follow the relationship shown by the
___________________ in the graph.
• It turns out that experiments show
that the wavelength of
electromagnetic waves emitted by a
blackbody actually follow the
______________ shown in the graph
called blackbody curves.
• Which curve is determined by the
temperature of the blackbody.
THE ULTRAVIOLET CATASTROPHE
This also suggests that light travels in _______ or
packets called ______ which behave like ________.
THE DUAL NATURE OF LIGHT