[10129761] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>

F
The figure shows the energy states of a certain atom. The atom is initially in state
S.

state energy
P 3 eV
Q 3.5 eV

R 5 eV

S 13 eV

Which of the following statements is/are correct?

(1) A photon of energy 8 eV can excite the atom to state R.
(2) A photon of energy 10 eV can excite the atom to state Q.
(3) Two photons each of energy 5 eV can excite the atom to state P.
A (1) only
B (1) and (2) only
C (1) and (3) only
D (2) and (3) only
A
[10130041] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of the following figures best shows the relatively sizes of the first four
orbits of the electron in a hydrogen atom?

C
[10130100] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 Which of the following types of EM waves can ionize hydrogen atoms in the
ground state?
Type of EM waves Wavelength / m
(1) Visible light 4  107 to 7  107
(2) Infra-red radiation 7  107 to 103
(3) Ultra-violet radiation 108 to 4  107
A (2) only
B (3) only
C (1) and (2) only
D (1) and (3) only
B

[10130412] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 Particles X and Y have the same mass. The de Broglie wavelength of X is  while
that of Y is 2. Which of the following statements is/are correct?
(1) If the momentum of Y is p, the momentum of X is 2p.
(2) If the kinetic energy of Y is E, the kinetic energy of X is 2E.
(3) If the speed of Y is v, the speed of X is 2v.
A (1) only
B (2) only
C (1) and (3) only
D (1), (2) and (3)
C

[10130480] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of the following particles has the longest de Broglie wavelength?
A An electron travelling at 3  104 m s1
B A proton travelling at 3  104 m s1
C An electron travelling at 3  105 m s1
D A proton travelling at 3  105 m s1
A
[10130596] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F

state

n=3

n=1

The electron transitions in hydrogen atoms from higher energy states to the
second excited state (n = 3) produces a set of spectral lines called the Paschen
series. Which of the following types of EM waves do these spectral lines consist
of? Given: the wavelength of visible light ranges from 400 nm to 700 nm.
(1) Visible light
(2) Infra-red radiation
(3) Ultra-violet radiation
A (1) only
B (2) only
C (3) only
D (1), (2) and (3)
B

[10130600] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 A certain atom in the ground state is excited by a photon of unknown wavelength.
The excited atom then drops back to the ground state and emits two photons one
after another. The wavelengths of the two photons are 1.22  107 m and 6.58 
107 m. What is the wavelength of the incident photon?
A 1.03  107 m
B 5.36  107 m
C 6.58  107 m
D 7.80  107 m
A
[10130660] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F


n=1

n=2

The electron transitions in hydrogen atoms from higher energy states to the first
excited state (n = 2) produces a set of spectral lines called the Balmer series. The
wavelength  of the spectral lines are given by the Balmer formula:

= n = 3, 4, 5…

Which of the following expressions gives the value of R in m1?

C 13.6

B
[10130803] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
When the electron in a hydrogen atom transits to a higher energy level, which of
the following quantities will increase?
(1) Total energy of the electron
(2) Radius of the electron’s orbit
(3) Angular momentum of the electron
A (3) only
B (1) and (2) only
C (2) and (3) only
D (1), (2) and (3)
D

[10130853] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 Which of the following electron transitions in a hydrogen atom requires the
largest amount of energy?
A From quantum number n = 1 to n = 2
B From quantum number n = 2 to n = 4
C From quantum number n = 3 to n = 6
D From quantum number n = 4 to n = 8
A

[10130957] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F


A large number of electrons of kinetic energy 11 eV are sent through some

hydrogen gas. Which of the following statements is/are correct?
(1) Some electrons are completely absorbed by the hydrogen atoms.
(2) Some hydrogen atoms are excited to higher energy states.
(3) No photons are emitted by the hydrogen atoms.
 A (2) only
B (3) only
C (1) and (2) only
D (1), (2) and (3)
A

[10130970] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of the following give(s) evidence to the suggestion that an atom has
discrete energy levels?
(1) The spectrum of light from a filament lamp
(2) The spectrum of light from a gas discharge tube
(3) Diffraction pattern formed by electrons
A (1) only
B (2) only
C (1) and (2) only
D (2) and (3) only
B

[10130985] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of following statements is correct?
(1) When light travels from air into water, its speed decreases and its wavelength
also decreases.
(2) When the speed of an electron decreases, the de Broglie wavelength of the
electron decreases.
(3) The quantization of angular momentum of the electron in a hydrogen atom
can be explained by the wave nature of electron.
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
B
[10131060] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F

The photo above shows the Fraunhofer lines. They are the spectral lines of the
sun. The formation of these dark lines is due to
A the excitation of photon.
B the absorption of photon by electron.
C the emission of photon by electron.
D the ionization of photon.
B

[10131234] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of the following can be the energies possessed by an electron in a
hydrogen atom?
(1) 0.2125 eV
(2) 0.85 eV
(3) 1.89 eV
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
A
[10131731] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
A student views a discharge tube containing low-density monatomic gas directly
with a plane transmission grating.

Which of the following spectra does the student observe?

A Continuous spectrum

B Continuous spectrum with discrete dark lines

C Discrete bright lines on a dark background

D Discrete bright lines on a dark background on one side and continuous

spectrum with discrete dark lines on the other side

C
[10131810] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Burning sodium in a flame gives out light of characteristic colour. The light
appears as a series of bright lines as shown below after passing through a
diffraction grating.

(Courtesy of NASA)
Which of the following statements about these bright lines are correct?
(1) The bright lines are produced by lights of different frequencies.
(2) The bright lines are the evidence of discrete energy levels of atoms.
(3) The pattern of the bright lines will be the same when sodium is replaced by
calcium.
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
A

[10131823] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Bohr introduced several postulates that made his model of atom different from
Rutherford’s. One of the postulates states that the total energy of an electron
staying in an orbit is
A increasing.
B decreasing.
C unchanged.
D uncertain.
C
[10132021] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
In the postulates of Bohr’s atomic model of hydrogen, some of their aspects are
considered as ‘classical’. Which of the following is not one of these ‘classical’
aspects?
A The electron is considered to be a particle.
B The electron can only occupy certain discrete orbits.
C The centripetal force is provided by the Coulomb force.
D The electron revolves around the nucleus in a circular orbit.
B

[10132155] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
The figure below shows the first three orbits that an electron can occupy in a
hydrogen atom.
n=1
electron
- n=2
+ n=3

nucleus

When the electron occupies the first orbit (n = 1), its total energy is E. What is the
electron’s energy when it occupies the third orbit (n = 3)?

C 3E
D 9E
A
[10132220] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
The figure below shows some possible energy levels of a hydrogen atom. P, Q, R
and S are some electron transitions between these energy levels.
Energy
n=4
P n=3
Q R
n=2
S

n=1

Which of the following statements about these electron transitions is/are correct?
(1) When transition Q occurs, the atom emits a photon.
(2) When transition S occurs, the energy change of the atom is 13.6 eV.
(3) The energy required for transition R is larger than that for transition P.
A (1) only
B (2) only
C (1) and (3) only
D (2) and (3) only
C

[10132251] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
A free electron is captured by an ionized hydrogen atom and drops to the fifth
excited state (n = 6). As a result, a photon is emitted. What is the minimum
energy of the photon?
A 0.378 eV
B 2.27 eV
C 11.3 eV
D 13.2 eV
A
[10132438] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
The light from a hot source passes through some gas at a low temperature. When
the light is viewed with a diffraction grating, a spectrum with a number of dark
lines is observed as shown below.

If the gas is removed, which of the following spectra will be observed?

A Continuous spectrum

B Continuous spectrum with discrete dark lines

C Discrete bright lines on a dark background

D Completely dark

[10132567] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
Which of the following has the longest wavelength?
A Red light
B Blue light
C An electron moving at 3  105 m s1
D A football of mass 0.45 kg moving at 40 m s1
A
[10132618] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
When the speed of an electron increases, which of the following quantities of the
electron also increase(s)?
(1) Momentum
(2) Wavelength
(3) Charge
A (1) only
B (3) only
C (1) and (2) only
D (2) and (3) only
A

[10132673] <lvl=easy><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
The figure below (drawn to scale) shows some electron transitions in an atom.
Which electron transition emits electromagnetic wave of the longest wavelength?
energy

P
Q R

A Transition P
B Transition Q
C Transition R
D Transition S
A
[10132739] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The figure below shows the lowest four energy levels of a mercury atom.

An electron in a mercury atom is raised to the 3rd excited state (n = 4). When the
electron returns to the ground state, one or more photons will be emitted. An
emitted photon may possess an energy of
(1) 1.6 eV.
(2) 3.9 eV.
(3) 8.8 eV.
A (1) only
B (3) only
C (1) and (2) only
D (2) and (3) only
D

[10132767] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The figure below shows part of the energy level diagram of a hydrogen atom.

A free electron of kinetic energy 12.4 eV collides with a hydrogen atom, which is
in the ground state. The change in kinetic energy of the hydrogen atom may be
neglected. Which of the following are the possible kinetic energy of the electron
after collision?
(1) 0.3 eV
(2) 2.2 eV
 (3) 9.0 eV
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
A

[10132830] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The figure below shows the first three orbits that an electron can occupy in an
hydrogen atom.
n=1
electron
- n=2
+ n=3

nucleus

When the electron occupies the second orbit (n = 2), its angular momentum is L.
What is the electron’s angular momentum when it occupies the third orbit (n = 3)?

B L

D 3L
C
[10132855] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The spectral lines in the Balmer series are formed by the transition of electrons
from higher excited states to the first excited state (n = 2) in a hydrogen atom. The
table below shows the wavelengths of the first four lines in the series obtained
from an experiment.
Order of spectral lines 1st 2nd 3rd 4th
Wavelength / nm 656 550 434 410
However, one of the measurements is incorrect. This spectral line is most likely
A the 1st line.
B the 2nd line.
C the 3rd line.
D the 4th line.
B

[10132888] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 A hydrogen atom is in its second excited state (n = 3). What is the minimum
frequency of photon that could ionize the atom?
A 2.05  1014 Hz
B 3.65  1014 Hz
C 2.92  1015 Hz
D 4.47  1016 Hz
B
[10132939] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The figure below (drawn to scale) represents some energy levels of a certain
atom. P, Q, R and S are electron transitions between these levels.
Energy

P
X Q

R
S

Transition X gives a yellow line in the spectrum. Which transition may give a red
line?
A Transition P
B Transition Q
C Transition R
D Transition S
A

[10133026] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The transitions of electrons between three energy states in a hydrogen atom result
in three spectral lines. The lowest and highest frequencies of these spectral lines
are f1 and f2 respectively. What is the frequency of the third spectral line?
A f2  f1

A
[10133043] <lvl=avg><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The figure below (drawn to scale) shows some energy levels of a certain atom.

Transition X results in the emission of a photon of wavelength . Which transition

would result in the emission of a photon of wavelength 2?
A Transition P
B Transition Q
C Transition R
D Transition S
A

[10133044] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The wavelength of photon emitted or absorbed when an electron in a hydrogen
atom undergoes a transition from one energy level to another is given by the

expression ab= . What is the value of ?

A 1.46  1026 m
B 9.14  108 m
C 13.6 eV
D 1.09  107 m
B
[10133051] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 The energy required to raise an electron in a hydrogen atom from the orbit n = 2
to n = 3 is E. What is the energy required to raise an electron in a hydrogen atom
from the orbit n = 3 to n = 4?

[10133238] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 A hydrogen atom in the ground state is excited by colliding with a free electron of
kinetic energy 12.4 eV. The excited hydrogen atom then emits light and returns to
the ground state. Which of the following wavelengths of light may be emitted?
(1) 97 nm.
(2) 103 nm.
(3) 122 nm.
A (1) and (2) only
B (1) and (3) only
C (2) and (3) only
D (1), (2) and (3)
C
[10133240] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 When a hydrogen atom in the third excited state (n = 4) is brought back to the
ground state (n = 1), it emits a photon of wavelength . What is the wavelength of
the photon emitted when a hydrogen atom drops from the third excited state (n =
4) to the first excited state (n = 2)?
A 2
B 3
C 4
D 5
D

[10133348] <lvl=dif><part=core><type=mc><cur=phy><mark=2><bk=E2><ch=02>
F
 When a hydrogen atom in the second excited state (n = 3) is brought back to the
ground state (n = 1), it emits a photon of frequency f. What is the frequency of the
photon emitted when a hydrogen atom in the third excited state (n = 4) is brought
back to the first excited state (n = 2)?
A 0.21f
B 0.375f
C 2.67f
D 4.74f
A