Do Now (3/6/14):
• What are the major topics in our Quantum
unit?
AP Quantum Quiz Review
3/6/14
AP Test Review Competition
• Winning group gets extra credit
#1
What is the term used to refer to the minimum
energy required for a photoelectron to escape
from a metal plate in a photocell?
a. Stopping voltage
b. Planck’s constant
c. Threshold wavelength
d. Work function
#2
• According to Einstein, the energy of a photon
depends on the ____________ of the
electromagnetic radiation.
a. Momentum
b. Speed
c. Frequency
d. Intensity
#3
What will likely happen if a light whose frequency
is below the threshold frequency hits a clean
metal surface?
a. No electron will be ejected from the metal
b. Fewer electrons will be ejected from the metal
c. More electrons will be ejected from the metal
d. Ejected electrons will have a higher kinetic
energy
#4
• When light is directed on a metal surface, the
kinetic energies of the electron:
a. Vary with the intensity of light
b. Vary with the frequency of light
c. Vary with the speed of light
d. Are random
#5
• Threshold frequency is to work function as
hertz is to which one of the following?
a. Coulomb
b. Joule
c. Newton
d. Watt
#6
• The variable that varies directly with the
amount of current produced by the
photoelectrons is:
a. The intensity of the incident light
b. The frequency of the incident light
c. The wavelength of the incident light
d. The work function of the metal surface
#7
• The threshold frequency has a value of X. If
the frequency of the incident light increase
from 2X to 4X, then the resulting current of
photoelectrons:
a. Is doubled
b. Is increased by a factor of 3
c. Is reduced by half
d. Remains the same
#8
• A scientist is trying to eject electrons from a
metal by shining a light on it, but none are
coming out. To eject electrons, she should
change the light by…
a. Decreasing the frequency
b. Increasing the frequency
c. Increasing the intensity
d. Increasing the wavelength
#9
• Which of the following statements is true
about a photon?
a. A photon has zero mass and zero momentum
b. A photon has finite mass and a finite value of
momentum
c. A photon has zero mass and a finite value of
momentum
d. A photon has finite mass but zero
momentum
#10
The work function of sodium is greater than that of
potassium. If both the surfaces are irradiated
with photons of the same wavelength, then the
KE of the photoelectrons in the sodium surface
as compared to the KE of the photoelectrons in
the potassium surface will be:
a. Same
b. Less
c. More
d. Cannot be determined
#11
In the Compton scattering experiment with X-rays
incident upon a carbon block, what happens to
the shift in wavelength as the scattering angle
becomes larger?
a. Increases
b. Decreases
c. Remains constant
d. Increases until it reaches maximum at 90°
#12
In the Compton scattering experiment, what
happens to the energy lost by the incident
photon?
a. It becomes the kinetic energy of the target
electron
b. It is emitted as a photon with higher frequency
c. It is emitted as a photon with lower frequency
d. It is absorbed by the target electron, causing the
electron to jump to an excited state
#13
The collision between a photon and a free
electron was first explained by which of the
following scientists?
a. Einstein
b. Heisenberg
c. Compton
d. Bohr
#14
• In the Compton Effect, a photon of
wavelength λ collides with a stationary
electron. The wavelength of the emitted
photon is:
a. Longer than λ
b. Shorter than λ
c. The same as λ
d. No photon is emitted
#15
• Which of the following objects would have the
longest de Broglie wavelength if they were
moving at the same speed?
a. Ping pong ball
b. Bowling ball
c. Bicycle
d. Bus
#16
Which of the following statements correctly
describes the de Broglie wavelength?
a. The higher the momentum of the object, the
longer the de Broglie wavelength
b. The lower the momentum of the object, the
longer de Broglie wavelength
c. The more mass the object has, the longer the
de Broglie wavelength
d. The faster the object moves, the longer the de
Broglie wavelength
#17
• According to de Broglie, the waves are
associated with:
a. Moving charged particles only
b. Moving neutral particles only
c. All particles
d. All moving particles
#18
• The de Broglie wavelength of a particle is
given by:
a. h+mv
b. hmv
c. h/mv
d. mv/c
e. mv
#20
A photon of energy E0 strikes a free electron, with
the scattered photon energy E moving in the
direction opposite that of the incident photon. In
this Compton effect interaction, the resulting
kinetic energy of the electron is:
a. E0
b. E
c. E0-E
d. E0+ E
e. Not given
#21
A photon of energy E0 strikes a free electron, with the
scattered photon energy E moving in the direction
opposite that of the incident photon. In this
Compton effect interaction, the resulting kinetic
energy of the electron is:
a. E0/c
b. < E0/c
c. > E0/c
d. (E0- E)/c
e. (E- E0)/c
#22
Five photons have the following energy values.
Which one represents the visible light
photon?
(a) 24.8 eV
(b)12.4 eV
(c) 6.2 eV
(d) 2.48 eV
(e) 1.24 eV
#22
• D. Photons in the visible region have wave length
range from 4000 Ǻ to 7000 Ǻ (approximately).
The product of the energy in eV and the wave
length in Angstrom in the case of any photon is
12400 (very nearly).
• The energy of the 4000 Ǻ photon in electron volt
is 12400/4000 = 3.1 eV.
• The energy of the 7000 Ǻ photon in electron volt
is 12400/7000 = 1.77 eV.
• Therefore, the photon in the visible region is
given in option (d).
#22
• If you were asked to calculate the wave length of
the photon of energy 2.48 eV, you will have
• λ = 12400/2.48 = 5000 Ǻ
• [You can calculate the wave length using the
relation E = hc/λ where E is the energy in joule, h
is Planck’s constant, c is the speed of light and λ is
the wave length (in metre). In the above problem
E = 2.48×1.6×10–19 joule (on converting the
energy in eV into joule), c = 3×108 ms–1and h =
6.6×10–34 Js. But this is time consuming].
#23
When electromagnetic radiations of wave length λ is
incident on a photosensitive surface, the kinetic energy
of the photoelectrons emitted from the surface is 2 eV.
When the wave length of the incident radiations is 2λ,
the kinetic energy of the photoelectrons emitted from
the surface is 0.5 eV. The threshold wave length
(maximum wave length) for photoelectric emission
from the surface is
(a) λ/2
(b) λ
(c) 3λ/2
(d) 2λ
(e) 3λ
#23
•
•
•
•
E. From Einstein’s equation, we have for the two cases
hc/λ = hc/λ0 + 2 eV and
hc/2λ = hc/λ0 + 0.5 eV
where h is Planck’s constant, c is the speed of light and
λ0 is the threshold wave length. We have expressed the
kinetic energy in electron volt itself for convenience,
with the understanding that all terms are in electron
volt.
• Multiplying the second equation by 4 and subtracting
the first equation from it, we obtain
• hc/λ = 3hc/λ0 from which λ0 = 3λ.
#24
Heisenberg’s Uncertainty Principle states:
(A) The more precise a particle’s energy can be
measured, the less precise its position can be
measured.
(B) A particle’s position can be measured exactly.
(C) A particle’s energy can be measured exactly.
(D) The more precise a particle’s momentum can be
measured, the less precise its position can be
measured.
(E) The more precise a particle’s momentum can be
measured, the less precise its energy can be
measured.
#25
Rutherford’s Gold Foil experiment caused a
modification of which of the following?
(A)Plum-pudding model of the atom
(B) Planetary model of the atom
(C) de Broglie hypothesis
(D) Wave nature of light
(E) Quantum theory of light
#26
In Rutherford’s Gold Foil experiment, most of the alpha
particles passed through the foil undeflected. Which
of the following properties of the atom can be
explained from this observation?
(A) The atom’s negative charge is concentrated in the
nucleus.
(B) The nucleus has electrons and protons.
(C) The atomic mass is distributed evenly throughout
the atom.
(D) The alpha particles can’t be deflected by electrons.
(E) The size of the nucleus is much less than the size of
the atom.
#27
Which of the following colors is associated with
the lowest temperature of a black body
radiator?
(A)Violet
(B) Blue
(C) Green
(D) Yellow
(E) Red
#28
Which of the following photons has the greatest
energy?
(A)Infrared
(B) Blue light
(C) X-ray
(D) Gamma ray
(E) Ultraviolet
#29
What did Max Planck propose to solve the black
body radiator problem?
(A)Radiation is made up of waves.
(B) Light changes its speed in different media.
(C) Light comes in packets of energy.
(D) Light has a continuous energy profile.
(E) Objects do not radiate energy.
#30
The energy of a photon depends on its:
(A) Amplitude
(B) Speed
(C) Temperature
(D) Pressure
(E) Frequency
#31
How does the energy of a photon change if the
wavelength is doubled?
(A)Doubles
(B) Quadruples
(C) Stays the same
(D) Is cut to one-half
(E) Is cut to one-fourth
#32
How does the momentum of a photon change if
the wavelength is halved?
(A)Doubles
(B) Quadruples
(C) Stays the same
(D) Is cut to one-half
(E) Is cut to one-fourth
#33
The photoelectric effect was explained by Albert
Einstein by assuming that:
(A)light is a wave.
(B) light is a particle.
(C) an electron behaves as a wave.
(D) an electron behaves as a particle.
(E) light does not interact with matter.
#34
The kinetic energy of photoelectrons depends
on the:
(A)speed of light.
(B) angle of illumination.
(C) intensity of the light.
(D) number of incident photons.
(E) photon frequency.
#35
The maximum kinetic energy of photoelectrons
depends on which of the following?
I. The light intensity
II. The frequency of the light
III. The material of the photoelectric cell
(A) Only I
(B) (B) Only II
(C) (C) Only III
(D) (D) Only I and II
(E) (E) Only II and III
#37
Classical physics could not explain the behavior
of a black body radiator at very short
wavelengths. What was this problem called?
(A) Absorption failure
(B) Ultraviolet Catastrophe
(C) Wavelength catastrophe
(D) Photoelectric Effect
(E) Radiation