問題一覧
1
Classical electromagnetic theory predicted that the energy radiated by a blackbody would become infinite as the wavelength of the radiation became shorter. The contradiction between observation and this result is called the.
Ultraviolet Catastrophe.
2
The blackbody
perfectly absorbs and emits all radiation.
3
The emission of electrons from a material surface occurs when light of certain frequencies shines on the surface of the material is called
photoelectric effect.
4
For a photoelectron to be emitted by a metal that is exposed to photons, the energy of the photons must be greater than the
metal’s work function.
5
No electrons are emitted if the frequency of the incoming light falls below a certain frequency, called the
threshold frequency (ft)
6
In the Bohr model of the atom,
Only specific electron orbits with given energies are stable.
7
The atom’s energy levels are depicted in an energy-level diagram,
the lower energy levels are separated by smaller amounts.
8
The observation that was not explained by the Rutherford model of the Atom is the —— spectra.
Emission
9
An electron in the Bohr model of the atom dropped from a Higher energy level to a Lower energy level and emitted a photon. This process is called
spontaneous emission.
10
According to the energy of a quantum of radiation, energy increases with
Frequency
11
The scattered waves had less energy and longer wavelengths than the incoming waves, this change in wavelength, known as the
compton shift
12
A photon with an energy of 3.5 eV is absorbed by a hydrogen atom. Afterwards, three photons are spontaneously emitted,
the sum of the emitted photon energies equals 3.5 eV.
13
Photon - ——— as they —- x to electrons.Photon wavelengths lengthen as they lose energy to electrons.
wavelengths lengthen - lose energy
14
Every element has a
distinct emission spectrum
15
A diagram or graph that indicates the wavelengths of radiant energy that a substance absorbs is called an
absorption spectrum
16
it is fundamentally impossible to make simultaneous measurements of a particle’s position and momentum with infinite accuracy.
Heisenberg’s uncertainty principle
17
The electron cloud’s density is greatest at the
Bohr radius.
18
Photons behave less like waves and more like particles as the frequency of the photons increases and the wavelength decreases.
true
19
The emission spectrum consists of .
narrow bright lines
20
According to Heisenberg’s uncertainty principle, the results of simultaneous measurement of momentum and location for a particle,
The more accurately one quantity is measured, the less accurately the other quantity is known
21
Which of the following phrases correctly describes a blackbody?
perfectly absorbs and emits all radiation
22
Classical electromagnetic theory predicted that the energy radiated by a blackbody would become infinite as the wavelength of the radiation became shorter. What was the contradiction between observation and this result called?
the ultraviolet catastrophe
23
Which of the following statements is true about the energy of a quantum of radiation?
Energy increases with frequency.
24
What is the energy of a photon with a frequency of 5.45 1014 Hz? (h = 6.63 10 34 J•s)
3.61 10 19 J
25
What is the frequency of a photon with an energy of 1.3 10 19 J? (h = 6.63 10 34 J•s)
2.0x 1014 Hz
26
For a photoelectron to be emitted by a metal that is exposed to photons, the energy of the photons must be greater than what property of the metal?
its work function
27
A metal with a work function of 3.5 eV is exposed to photons with an energy of 3.7 eV. What is the maximum kinetic energy of the emitted photoelectrons?
0.2 eV
28
Which of the following statements correctly describes the Compton shift that occurs when photons scatter from electrons?
Photon wavelengths lengthen as they lose energy to electrons.
29
What did Rutherford’s experiment demonstrate?
The atomic nucleus was a small, compact region of positive charge.
30
What observation was not explained by the Rutherford model of the atom?y
emission spectra
31
Which of the following statements is true about an emission spectrum?
It consists of narrow bright lines.
32
What type of spectrum is observed in the light from the sun and other stars?
an absorption spectrum
33
By what process does an electron in the Bohr model of the atom drop from a higher-energy level to a lower-energy level and emit a photon?
spontaneous emission
34
Which of the following is a feature of the Bohr model of the atom?
Only specific electron orbits with given energies are stable.
35
Which of the following statements correctly describes an atom’s energy levels as they are depicted in an energy-level diagram?
The higher energy levels are separated by smaller amounts.
36
A photon with an energy of 2.86 eV is absorbed by a hydrogen atom. Afterwards, three photons are spontaneously emitted. Which statement correctly describes the emitted photons?
The sum of the emitted photon energies equals 2.86 eV.
37
At what point do photons behave less like waves and more like particles?
as the frequency of the photons increases
38
Which of the following phenomena is the result of light’s wave properties?
two-slit interference
39
Which of the following experiments indicated that matter waves exist?
the diffraction of electrons by a single crystal
40
What is the momentum of a proton with a de Broglie wavelength of 6.63 10 9 m? (h = 6.63 10 34 J•s)
1.00 10 25 kg•m/s
41
. According to the matter-wave modification to the Bohr model of the atom, what do the orbits of electrons in an atom resemble?
standing waves
42
Which of the following statements correctly describes the results of simultaneous measurement of momentum and location for a particle?
The more accurately one quantity is measured, the less accurately the other quantity is known.
43
Which of the following indicates the greatest probability for an electron’s position in the ground state of a hydrogen atom?
the middle of the peak of the probability curve
44
Which of the following does not describe the electron cloud for an electron in the ground state of a hydrogen atom?
The electron cloud’s density is uniformly constant throughout.