Section 27.1
A Particle Model of Waves
Practice Test
1.
When light with a frequency greater than
f
0
ejects an electron, the excess energy, _________, becomes the __________.
a.
hf
; potential energy of the electron
b.
hf
0
; kinetic energy of the photon
c.
hf
-
hf
0
; kinetic energy of the electron
d.
hf
0
-
hf
; potential energy of the photon
Hint
2.
The __________ is the minimum frequency of radiation required in order to eject electrons from a metal.
a.
de Broglie wavelength
b.
kinetic frequency
c.
photon momentum
d.
threshold frequency
Hint
3.
According to Einstein, light and other forms of radiation consist of discrete bundles of energy that were later called __________.
a.
positrons
b.
photons
c.
quarks
d.
comptons
Hint
4.
The stopping potential,
V
0
, that prevents electrons from flowing across a certain photocell is 6.0 V. What is the kinetic energy in J given to the electrons by the incident light?
a.
1.60×10
-19
J
b.
6.9×10
-19
J
c.
6.4×10
-19
J
d.
9.6×10
-19
J
Hint
5.
Planck was able to calculate the shape of the spectra of incandescent bodies by hypothesizing that __________.
a.
energy is continuous
b.
energy of vibration is equal to the frequency of vibration multiplied by an integer
c.
energy is not continuous
d.
energy of vibration could have any frequency
Hint
6.
The __________ effect is the emission of electrons produced when electromagnetic radiation falls on certain metals.
a.
electromagnetic
b.
photomagnetic
c.
ultraviolet
d.
photoelectric
Hint
7.
What is the momentum of a photon of green light that has a wavelength of 520 nm?
a.
1.3×10
-27
kg·m/s
b.
3.1×10
-27
kg·m/s
c.
1.1×10
-26
kg·m/s
d.
2.6×10
-27
kg·m/s
Hint
8.
Which of the following was a problem that could not be explained by Maxwell's wave theory?
a.
production of changing magnetic field by a changing electric field
b.
production of electric and magnetic fields that move through space
c.
oscillation of electric fields moving away from an antenna
d.
emission of electrons produced when electromagnetic radiation falls on certain metals
Hint
9.
According to Einstein, the energy of a photon depends on the __________ of the electromagnetic radiation.
a.
momentum
b.
intensity
c.
speed
d.
frequency
Hint
10.
Which of the following equations represents the momentum of a photon?
a.
p
=
h
/
λ
b.
E
=
mc
2
c.
p
=
hf
d.
λ
=
h
/
mv
Hint
11.
An electron is accelerated by a potential difference of 120 V. What is the speed of the electron?
a.
2.7×10[supersctip 6 m/s
b.
7.1×10
6
m/s
c.
5.9×10
6
m/s
d.
6.5×10
6
m/s
Hint
12.
Compton observed an increase in wavelength with scattered X rays, which meant that the X-ray photons had _________________.
a.
gained energy only
b.
gained both energy and momentum
c.
lost momentum only
d.
lost both energy and momentum
Hint
13.
The work function for a certain element is 2.87 eV. What is its threshold wavelength?
hc
= 1240 eV·nm
a.
495 nm
b.
446 m
c.
356 nm
d.
432 nm
Hint
14.
The work function of iron is 4.7 eV. What is the threshold wavelength of iron?
a.
2600 nm
b.
2.60 nm
c.
470 nm
d.
260 nm
Hint
15.
Electrons are ejected from a metal if the __________ of radiation falling on it is __________.
a.
frequency; below the threshold frequency
b.
intensity; below the threshold intensity
c.
intensity; above the threshold intensity
d.
frequency; above the threshold frequency
Hint
16.
Einstein predicted that photons had two properties of particles: __________ and __________.
a.
momentum; diffraction
b.
energy; mass
c.
energy; momentum
d.
mass; momentum
Hint
17.
The threshold frequency of tin is 1.2×10
15
Hz. What is the threshold wavelength?
a.
4.4×10
-6
m
b.
2.5×10
-7
m
c.
3.3×10
-7
m
d.
9.83×10
-6
m
Hint
18.
The threshold frequency is the frequency at which kinetic energy is equal to __________.
a.
hf
0
b.
zero
c.
hf
d.
h
Hint
