Q8.2.a: What is the energy of the sixth electronic energy level (N=6)
of a hydrogen atom?
1) – 13.6 eV
2) – 2.27 eV
3) + 2.27 eV
4) – 0.38 eV
5) + 0.38 eV
En =
-13.6
-13.6
® E6 =
= -0.38 eV
n2
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Q.8.2.b
A hydrogen atom is initially in the excited state
(N = 4). It emits a photon and ends up in the state (N = 2).
Which of the arrows in the diagram represents this process? 5
Q.8.2.c
A hydrogen atom is initially in the excited state
(N = 4). It emits a photon and ends up in the state (N = 2).
What is the energy of the emitted photon?
1) E4 – E2
2) E2 – E4
3) E4
4) E2
5) |E4|
6) |E2|
Q8.2.d Photon emission
Suppose that these are the
quantized electronic energy levels
(K+U) for an atom. If the atom is
excited to the second excited
state (marked by a dot), what are
the possible energies of photons it
might emit?
1) 2, 5, and 9 eV
2) 3, 4, and 7 eV
3) 3 or 7 eV
4) 5 or 9 eV
5) 2 eV
Q.8.2.e
A hydrogen atom is initially in the ground state. It absorbs a
photon. This results in ionization of the atom: H  H+ + e–
If the separated proton and electron have zero kinetic energy,
what was the energy of the absorbed photon?
1) 13.6 eV
2) –13.6 eV
3) > 13.6 eV
4) < 13.6 eV
5) 0 eV
Chapter 8 Clicker A Answers
1
Q8.2.f Photon absorption
Imagine an atom which only has two electronic energy levels. The ground
state energy is –3.0 eV and the excited state has an energy of –1.1 eV.
I irradiate a sample containing many atoms with visible light which contains
photons of all energies from 1.8 eV up to 3.1 eV.
What are the energies of the photons that are absorbed, and therefore are
not detected in the outgoing light beam?
1) The detector will detect
photons of all energies – none
are missing.
2) 1.1 eV
3) 3.0 eV and 1.1 eV
4) 3.0 eV
5) 1.9 eV
Q8.2.g Electron excitation of a gas
Suppose that these are the quantized energy
levels (K+U) for an atom. Initially the atom is in
its ground state (symbolized by a dot). An
electron with kinetic energy
6 eV collides with the atom and excites it. What
is the remaining kinetic energy of the electron?
1) 9 eV
2) 6 eV
3) 5 eV
4) 3 eV
5) 2 eV
Q8.3.a Photon absorption, cold sample
Light consisting of photons with a
range of energies from 1 to 7.5
eV passes through this collection
of objects.
A collection of these atoms is kept
very cold, so that all are in the
ground state.
What photon energies will be
absorbed from the incoming light
beam, and therefore will not be
detected in the outgoing beam
(“dark lines”)?
1) 2 eV, 5 eV, 9 eV
2) 3 eV, 4 eV
3) 0.5 eV, 3 eV, 4 eV
4) 4 eV, 7 eV
5) 3 eV, 4 eV, 7 eV
6) None of the above
Q8.3.b Photon absorption, cold sample
Light consisting of photons with a
range of energies from 1 to 3 eV
passes through this collection of
objects.
A collection of these atoms is
kept very cold, so that all are in
the ground state.
Chapter 8 Clicker A Answers
What photon energies will be
absorbed from the incoming light
beam, and therefore will not be
detected in the outgoing beam
(“dark lines”)?
1) 2 eV, 5 eV, 9 eV
2) 3 eV, 4 eV
3) 0.5 eV, 3 eV, 4 eV
4) 4 eV, 7 eV
5) 3 eV, 4 eV, 7 eV
6) None of the above
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