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