Transcript Modern Physics Review

Modern Physics Review
Get a board, marker, partner, and
wipey thing
Which phenomenon can be
explained by both the particle
model and wave model?
1.
2.
3.
4.
Polarization
Reflection
Interference
diffraction
A sound wave cannot be . . .
1.
2.
3.
4.
Reflected
Refracted
Diffracted
polarized
Describe the photoelectric
effect

UV light was shot at a zinc plate
and electron were emitted
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Electrons only jumped when the
light was above a threshold
frequency

Light can transfer energy, a
matter property
Monochromatic light strikes a metal
surface that has a work function of 6.7
x 10-19 J. Each photon has an energy
of 8.0 x 10-19 J
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What is the maximum KE of the
photoelectrons?
1.3 x 10-19 J
What is this energy in eV?
0.81 eV
E-m radiation of constant
frequency incident on a
photoemissive material causes
the emission of photoelectrons. If
the intensity of this radiation is
increased, what will happen to the
number of the emissions of
photoelectrons?
Draw a graph of the photocurrent
of photoelectrons (Y) vs. Intensity
of the incident light (X)
What is the relationship between
intensity of light and current?
4.0 x
-19
10
J
How much energy will a blue light
with a frequency of 6.0 x 1014 Hz
have?
The wavelength of photon A is
greater than that of photon B.
Compared to the energy of photon
A the energy of photon B is . . .
E = hc/λ
The ratio of the energy of a
quantum of electromagnetic
radiation to its frequency is called:
See the handout graph:
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What is the slope of the line?
What is the threshold frequency
of metal A?
Who discovered the property
expressed in this graph?
What did this discovery prove?
Compared to the Work function
of B, the W0 of A is . . .
Metal B

Monochromatic light hits both
metals. Which source will emit
photoelectrons with the least
energy?
Which color of visible light has the
greatest energy per photon?
Which phenomenon can only be
explained by assuming that light is
quantized?
Describe the Compton Effect?

Light has the ability to transfer
momentum

Therefore it has particle
properties
As the wavelength of a photon
decreases, what happens to its
momentum?
p = h/λ
What is the momentum of a
photon of light whose wavelength
is 5.0 x 10-7-m?
1.326 x
-27
10
kg m/s
If the wave properties of a particle
are difficult to observe, it is
probably due to the particles. . .
What did the following
physicists have to say . . .

DeBroglie
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Heisenberg
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Matter should have wave
characteristics
Nothing can be certain without
and experiment
An electrons position and
momentum cannot both be
known
Schrodinger

A cat is alive and dead until
looked at.
The “electric eye” on the gym
partition makes use of the
photoelectric effect. What other
devices make use of this effect?