Review for exam 1

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Review for exam 1

• Please bring a scan tron form 882-e

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Ch. 37 Relativity

• Straightforward time dilation and length
  contraction.
• A simple relative velocity problem (see example
  herein)
• Relativistic energy and momentum
• No relativistic doppler shift
• Basic idea behind general relativity

3
Q37.1
As a high-speed spaceship flies past you at half
the speed of light, it fires a strobe light. An
observer on board the spaceship measures a
spherical wave front that spreads away from the
strobe light with the same speed c in all
directions. The wave front that you measure
A. is spherical and remains centered on the
spaceship as it moves. B. is spherical and is
centered on the point where the spaceship was
when the strobe was fired. C. is not spherical,
but remains centered on the spaceship as it
moves. D. is not spherical, but is centered on
the point where the spaceship was when the strobe
was fired.
4
A37.1
As a high-speed spaceship flies past you at half
the speed of light, it fires a strobe light. An
observer on board the spaceship measures a
spherical wave front that spreads away from the
strobe light with the same speed c in all
directions. The wave front that you measure
A. is spherical and remains centered on the
spaceship as it moves. B. is spherical and is
centered on the point where the spaceship was
when the strobe was fired. C. is not spherical,
but remains centered on the spaceship as it
moves. D. is not spherical, but is centered on
the point where the spaceship was when the strobe
was fired.
5
Q37.2
As a high-speed spaceship flies past you at half
the speed of light, a strobe light fires at the
center of a room aboard the spaceship. As
measured by you, the light from the strobe
A. reaches point A before it reaches point B. B.
reaches point B before it reaches point A. C.
reaches points A and B simultaneously. D. not
enough information given to decide
6
A37.2
As a high-speed spaceship flies past you at half
the speed of light, a strobe light fires at the
center of a room aboard the spaceship. As
measured by you, the light from the strobe
A. reaches point A before it reaches point B. B.
reaches point B before it reaches point A. C.
reaches points A and B simultaneously. D. not
enough information given to decide
7
Q37.6
Santiago stands on the ground as Miriam flies
directly toward him in her spaceship at 0.5c. She
fires a small rocket directly toward Santiago
that flies at a speed of 0.8c relative to her
spaceship. According to Santiago, the speed of
the rocket is
A. 1.3c. B. faster than c but slower than
1.3c. C. c. D. faster than 0.8c but slower than
c. E. 0.8c.
8
A37.6
Santiago stands on the ground as Miriam flies
directly toward him in her spaceship at 0.5c. She
fires a small rocket directly toward Santiago
that flies at a speed of 0.8c relative to her
spaceship. According to Santiago, the speed of
the rocket is
A. 1.3c. B. faster than c but slower than
1.3c. C. c. D. faster than 0.8c but slower than
c. E. 0.8c.
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Q37.7
According to the relativistic expression for
momentum, if the speed of an object is doubled,
the magnitude of its momentum
A. increases by a factor greater than 2. B.
increases by a factor of 2. C. increases by a
factor greater than 1 but less than 2. D. The
answer depends on the value of the initial speed.
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A37.7
According to the relativistic expression for
momentum, if the speed of an object is doubled,
the magnitude of its momentum
A. increases by a factor greater than 2. B.
increases by a factor of 2. C. increases by a
factor greater than 1 but less than 2. D. The
answer depends on the value of the initial speed.
11
Q37.8
According to the relativistic expression for
kinetic energy, the kinetic energy of an object
of mass m moving with speed v
A. is equal to (1/2)mv2. B. is less than
(1/2)mv2. C. is greater than (1/2)mv2. D. depends
on the value of the speed.
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A37.8
According to the relativistic expression for
kinetic energy, the kinetic energy of an object
of mass m moving with speed v
A. is equal to (1/2)mv2. B. is less than
(1/2)mv2. C. is greater than (1/2)mv2. D.
depends on the value of the speed.
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Ch. 38 Photons, electrons, atoms

• Energy of a photon
• Photoelectric effect
• Energy levels and photons
• Rutherford scattering nucleus is small!
• Bohr model for hydrogen
• Quantization of angular momentum
• Laser
• Compton scattering
• Blackbody radiation

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Q38.1
In an experiment to demonstrate the photoelectric
effect, you shine a beam of monochromatic blue
light on a metal plate. As a result, electrons
are emitted by the plate. If you increase the
intensity of the light but keep the color of the
light the same, what happens?
A. More electrons are emitted per second. B. The
maximum kinetic energy of the emitted electrons
increases. C. both A. and B. D. neither A. nor B.
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A38.1
In an experiment to demonstrate the photoelectric
effect, you shine a beam of monochromatic blue
light on a metal plate. As a result, electrons
are emitted by the plate. If you increase the
intensity of the light but keep the color of the
light the same, what happens?
A. More electrons are emitted per second. B. The
maximum kinetic energy of the emitted electrons
increases. C. both A. and B. D. neither A. nor B.
16
Q38.2
This graph in shows the stopping potential as a
function of the frequency of light falling on a
metal surface. If a different type of metal is
used,
A. the graph could have a different slope. B.
the graph could intercept the horizontal axis at
a different value. C. both A. and B. D. neither
A. nor B.
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A38.2
This graph in shows the stopping potential as a
function of the frequency of light falling on a
metal surface. If a different type of metal is
used,
A. the graph could have a different slope. B.
the graph could intercept the horizontal axis at
a different value. C. both A. and B. D. neither
A. nor B.
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Q38.3
A certain atom has two energy levels whose
energies differ by 2.5 eV. In order for a photon
to excite an electron from the lower energy level
to the upper energy level, what must be true
about the energy of the photon?
A. Its energy must be greater than or equal to
2.5 eV. B. Its energy must be exactly 2.5 eV. C.
Its energy must be less than or equal to 2.5
eV. D. none of the above
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A38.3
A certain atom has two energy levels whose
energies differ by 2.5 eV. In order for a photon
to excite an electron from the lower energy level
to the upper energy level, what must be true
about the energy of the photon?
A. Its energy must be greater than or equal to
2.5 eV. B. Its energy must be exactly 2.5 eV. C.
Its energy must be less than or equal to 2.5
eV. D. none of the above
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Q38.4
A certain atom has only three energy levels. From
lowest to highest energy, these levels are
denoted n 1, n 2, and n 3. When the atom
transitions from the n 3 level to the n 2
level, it emits a photon of wavelength 800 nm.
When the atom transitions from the n 2 level to
the n 1 level, it emits a photon of wavelength
200 nm. What is the wavelength of the photon
emitted when the atom transitions from the n 3
level to the n 1 level?
A. 1000 nm B. 600 nm C. 500 nm D. 160 nm
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A38.4
A certain atom has only three energy levels. From
lowest to highest energy, these levels are
denoted n 1, n 2, and n 3. When the atom
transitions from the n 3 level to the n 2
level, it emits a photon of wavelength 800 nm.
When the atom transitions from the n 2 level to
the n 1 level, it emits a photon of wavelength
200 nm. What is the wavelength of the photon
emitted when the atom transitions from the n 3
level to the n 1 level?
A. 1000 nm B. 600 nm C. 500 nm D. 160 nm
22
Q38.5
In the Bohr model of the hydrogen atom, an
electron in the n 2 orbit has
A. a higher total energy and a higher kinetic
energy than an electron in the n 1 orbit. B. a
lower total energy and a higher kinetic energy
than an electron in the n 1 orbit. C. a higher
total energy and a lower kinetic energy than an
electron in the n 1 orbit. D. a lower total
energy and a lower kinetic energy than an
electron in the n 1 orbit. E. none of the above
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A38.5
In the Bohr model of the hydrogen atom, an
electron in the n 2 orbit has
A. a higher total energy and a higher kinetic
energy than an electron in the n 1 orbit. B. a
lower total energy and a higher kinetic energy
than an electron in the n 1 orbit. C. a higher
total energy and a lower kinetic energy than an
electron in the n 1 orbit. D. a lower total
energy and a lower kinetic energy than an
electron in the n 1 orbit. E. none of the above
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Q38.6
When an x-ray photon bounces off an electron,
A. the photon wavelength decreases and the photon
frequency decreases. B. the photon wavelength
decreases and the photon frequency increases. C.
the photon wavelength increases and the photon
frequency decreases. D. the photon wavelength
increases and the photon frequency increases. E.
none of the above
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A38.6
When an x-ray photon bounces off an electron,
A. the photon wavelength decreases and the photon
frequency decreases. B. the photon wavelength
decreases and the photon frequency increases. C.
the photon wavelength increases and the photon
frequency decreases. D. the photon wavelength
increases and the photon frequency increases. E.
none of the above
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Q38.7
If you increase the temperature of a blackbody,
A. it emits more radiation at very short
wavelengths and more radiation at very long
wavelengths. B. it emits more radiation at very
short wavelengths but less radiation at very long
wavelengths. C. it emits less radiation at very
short wavelengths but more radiation at very long
wavelengths. D. it emits less radiation at very
short wavelengths and less radiation at very long
wavelengths. E. none of the above
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A38.7
If you increase the temperature of a blackbody,
A. it emits more radiation at very short
wavelengths and more radiation at very long
wavelengths. B. it emits more radiation at very
short wavelengths but less radiation at very long
wavelengths. C. it emits less radiation at very
short wavelengths but more radiation at very long
wavelengths. D. it emits less radiation at very
short wavelengths and less radiation at very long
wavelengths. E. none of the above
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Ch. 39 The wave nature of particles

• deBroglie wavelength
• Diffraction of electrons confirmed the wave
  nature of particles
• Heisenberg uncertainty principle
  (momentum-position, energy-time)
• Wave function, probability distribution function,
  stationary state
• 1-D Schrodinger equation

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Q39.1
In order for a proton to have the same momentum
as an electron,
A. the proton must have a shorter de Broglie
wavelength than the electron. B. the proton must
have a longer de Broglie wavelength than the
electron. C. the proton must have the same de
Broglie wavelength as the electron. D. not enough
information given to decide
30
A39.1
In order for a proton to have the same momentum
as an electron,
A. the proton must have a shorter de Broglie
wavelength than the electron. B. the proton must
have a longer de Broglie wavelength than the
electron. C. the proton must have the same de
Broglie wavelength as the electron. D. not enough
information given to decide
31
Q39.2
An electron is accelerated from rest by passing
through a voltage Vba. The final wavelength of
the electron is ?1. If the value of Vba is
doubled, the wavelength of the accelerated
electron (assumed to be nonrelativistic) changes
to
A. B. C. D. E. none of the above
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A39.2
An electron is accelerated from rest by passing
through a voltage Vba. The final wavelength of
the electron is ?1. If the value of Vba is
doubled, the wavelength of the accelerated
electron (assumed to be nonrelativistic) changes
to
A. B. C. D. E. none of the above
33
Q39.3
A beam of electrons passes through a narrow slit.
The electrons land on a distant screen, forming a
diffraction pattern. In order for a particular
electron to land at the center of the diffraction
pattern, it must pass
A. through the center of the slit. B. through the
upper half of the slit. C. through the lower half
of the slit. D. impossible to decide
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A39.3
A beam of electrons passes through a narrow slit.
The electrons land on a distant screen, forming a
diffraction pattern. In order for a particular
electron to land at the center of the diffraction
pattern, it must pass
A. through the center of the slit. B. through the
upper half of the slit. C. through the lower
half of the slit. D. impossible to decide
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Q39.4
An electron is free to move anywhere within a
cube of copper 1 cm on a side. Compared to an
electron within a hydrogen atom, the electron in
copper
A. has a much smaller uncertainty in momentum. B.
has a slightly smaller uncertainty in
momentum. C. has the same uncertainty in
momentum. D. has a slightly larger uncertainty in
momentum. E. has a much larger uncertainty in
momentum.
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A39.4
An electron is free to move anywhere within a
cube of copper 1 cm on a side. Compared to an
electron within a hydrogen atom, the electron in
copper
A. has a much smaller uncertainty in momentum. B.
has a slightly smaller uncertainty in
momentum. C. has the same uncertainty in
momentum. D. has a slightly larger uncertainty in
momentum. E. has a much larger uncertainty in
momentum.
37
Q39.5
The graph shows the real and imaginary parts of a
particular wave function for a free particle. At
which value(s) of x is there zero probability of
finding the particle?
A. x 0 B. x p/2k C. x p/k D. x 3p/2k E.
none of these
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A39.5
The graph shows the real and imaginary parts of a
particular wave function for a free particle. At
which value(s) of x is there zero probability of
finding the particle?
A. x 0 B. x p/2k C. x p/k D. x 3p/2k E.
none of these
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Q39.6
The graph shows the real part of a particular
wave function for a free particle. The
quantum-mechanical state represented by this wave
function
A. has definite momentum and definite energy. B.
has definite momentum, but not definite
energy. C. has definite energy, but not definite
momentum. D. has neither definite energy nor
definite momentum.
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A39.6
The graph shows the real part of a particular
wave function for a free particle. The
quantum-mechanical state represented by this wave
function
A. has definite momentum and definite energy. B.
has definite momentum, but not definite
energy. C. has definite energy, but not definite
momentum. D. has neither definite energy nor
definite momentum.