Atomic and Nuclear Physics
Calculate the first excitation energy of the atom.
1.60 x 10-19 J
1.02 x 10-18 J
1.60 x 10-18 J
1.02 x 10 j
If the atom de-excites from n=2, the wavelength of the emmited radiation is
2.4 x 10-7 m
1.2 x 10-7 m
2.4 x 10-9 m
1.2 x 10-9 m
Two isotopes of uranium are designated as 238 U and 235 U . The 238 and 235 represent their
The main difference between x-rays and y-rays lies in their
mode of production
mode of propagation
An electron mass 9.1 x 10-31 kg moves with a speed of 107 ms-1. Calculate the wavelength of the associated wave. [h= 6.6 x 10-34 Js]
9.10 x 10-24 m
4.55 x 10-17 m
7.25 x 10-11 m
6.20 x 10-8 m
Both γ rays and X- rays ;
I. can be produced by thermionic emission
II. have low frequencies
III. have short wavelengths . Which of the statements above is /are correct?
I and III only
When a radioactive substance undergoes a beta decay, its
mass number decreases by 1
atomic number decreases by 1
mass number increases by 1
atomic number increases by 1
Nuclear fission is preferred to nuclear fusion in the generation of energy because
very high temperature s are required for fusion
the raw materials for fusion are easily obtained
energy obtained from fusion is relatively smaller
the by products of fusion are very dangerous
Control in nuclear reactors is effected with boron rods because the rods have ability to
slow down neutrons
A radioactive elements has a decay constant of 0.777s-1 calculate its half-life
Which of the following electromagnetic waves can be detected by its heating effect?
If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer
an explosion s observed
the rainbow colours are seen
an emission spectrum is observed
dark lines are observed
The number of protons in an element increased by one after radioactive decay. The element must have decayed by emitting
a beta particle
an alpha particle
a gamma ray
The correct sequence of energy transformations in the operation of an X-ray tube is
II. Kinetic energy of thermo electrons
III. Potential energy of the target atoms
IV. Heat energy of the emitted electrons
IV, III, II,I
IV, II, III
II, IV, III, I
In a nuclear reactor, chain reactions result from the release of
The breaking up of an atomic nucleus into two fragments of nearly equal sizes is known as
A 500 kV is applied across an X-ray tube. Caculate the maximum velocity of the electrons produced [ Me=9.1 x 10-31 kg, e = 1.6 x 10-19 C]
4.2 x 105 ms-1
1.8 X 108 ms-1
4.2 x 105 ms-1
1.8 x 105 ms-1
A radioactive substance of mass 768g has a half life of 3 years. After how many years does this substance leave only 6g undecayed ?
Fusion is not usually used for generating electric power because
no energy is released when fusion takes place
very high temperatures are required to initiate fusion reaction
the raw materials needed are not easily available
heavy nuclei are involved
An atom 234/91 P emits a gamma radiation. The resultant nuclide is
Which of the following statements is an advantage of nuclear fusion over nuclear fission?
The resulting chain reaction which produces large amount of energy
No radioacvtive waste is produced as by-product
Very high temperatures required in the process
The end product is lead
Beta particles are fast-moving
A process by which two light atoms join to form a new atom of higher atomic mass is
Light of the energy 5.0e V falls on a metal of work function 3.0eV and electrons are emitted. Determine the stopping potential. [ electronic charge, e=1.60 x 10-19 C]
In which of the following devices is the principle of photoeletric effect not applicable?
Closed-circuit television camera
Which of the following statements about X-rays is not correct? They
are electromagnetic waves
can be used to study crystal lattice
can destroy living cells
are produced from the nucleus of an atom
A radioactive substance has a half-life of 3 days. If a mass of 1.55g of this substance is left after decaying for 15 days, determine the original value of the mass.
Which of the following representations is correct for an atom X with 28 electrons and 30 neutrons ?
Which of the following statements is true of ultra violet radiations? It
supports the sensation of hearing
does not cause the emission of electrons from metals
is an electromagnetic wave
is not capable of causing sun bum
Which of the following statements is not true of the isotopes of an element? They
are atoms of the same element
have the same chemical properties
have the same atomic number
have the same mass number
A radioactive element has a decay constant of 0.077 s-1 calculate its half life
The minimum energy required to remove an electron from an atom is known as
Nuclear fussion is preferred to nuclear fussion in the generation of energy because
very high temperatures are equired for fussion
the raw materials for fussion are not easily obtained
energy obtained from fussion is relatively smaller
the byproduct of fussion are very dangerous
Which of the following reactions represents nuclear fussion?
2/1H + 2/1 H - 2/3He + 1/0n
235/92 U + 1/0 n→145/56 Ba + 90/36Kr + 2 1/0 r
234/90 Th → 1/0 n + 234/94 Pa
U 288/92 → 4/2 He + 234/90 Th
In a model of the hydrogen atom, the energy levels atom, the energy levels Wn are given by the formula Wn = R/n2 . where the n is an integer and R is a consant . Determine the energy released in the transition from n = 3 to n=2
If a radioactive atom emits a beta particle, its mass number
increases by one
remains the same
decreases by one
increases by two
When the light falls on a metallic surface, the number of electrons that may be emitted would depend solely on the
area of the metalic surface
frequency of the light
intensity of the light
time of exposure of the metalic surface to light
Which of the following materials is used to control the rate of neutron production in a nuclear reactor?
Which of the following is usually used to cause fission in an atomic reactor?
A nuclide X is produced by bombarding a nitrogen (N) nucleus with an alpha (α) particle with the release of heavy hydrogen (D) nucleus as shown by the following nuclear equation
α+14 N p X 2 D
7 q + 1
Determine the values of p and qw in the equation
12 and 6
14 and 7
16 and 8
19 and 8
In which of the following transitions is the largest quantum of energy liberated by an hydrogen atom when the electron changes energy levels? [n is the quantum number]
n=2 to n=1
n=1 to n=2
n=2 to n=3
n=3 to n=2
Production of x-rays in an x-ray tube begins with
photo electric emission
collision of electrons
field emission of electrons
The nucleon number and the proton number of a neutral atom of a n element are 23 and 11 respectively. How many neutrons are present in the atom?
A nitrogen nucleus bombared with an alpha particle produces an oxygen nucleus and a proton. The nuclear reaction for this process is 4/7He +14/7 N 17/6 O +1/1H + Q . Which of the following statements about the reaction is not correct?
The bombardment results into nucleus with greater proton number
It is an induced nuclear reaction
It is a natural radioactive decay
The sum of the initial nucleon numbers is equal to the sum of the final nucleon numbers
In a nuclear reactor, electricity can be generated through the following processes. Arrange the process in the correct order.
I. The steam is used to drive turbines.
II. The heat energy released is removed by passing water through the reactor.
III. The turbines in turn generate electricity.
IV. The water then passes through some form of heat exchanger to produce steam.
II, IV,I and II
I,II, III and IV
III, I, IV
IV, I, III and II
Electrons passing through crystals are diffracted because they
are repelled by atoms in the cystals
are attracted by the atoms in the cystal
posses wave properties
The duality of matter implies that matter
exists as a particle of dual composition
has momentum and energy
has both wave and particle properties
is made up of dual materials
A nuclide Y emits in succession an α-particle and a β- particle. the atomic number of the resulting nuclide is
The half life of a radioactive substance is 14 days. If 48g of this substance is stored, after how many days will 1.5g of the original substance remain?
A material of mass 1.0 x 10-3 kg undergoes a fission process which decreases its mass by 0.02 percent. Caculate the amount of energy released in the process . [c= 3.0 x 108 ms-1]
1.8 x 1020 J
1.8 x 1013 J
1.8 x 1011 J
1.8 x 1010 J
Absorption line spectra exhibited by atoms is a result of
change in kinetic energy of a moving atom
instability of the nucleons
excitation of an electron in the atom
transition of an electron from a higher to a lower energy level
Bohr's atomic model proves most sucessful for the explanation of the :
I. structure of hydrogen atom;
II. line spectra of the hydrogen atom;
III. multi- electron atoms .
Which of the statements above is/are correct?
I and II only
I and III only
The diagram illustrates the energy trasitions of five electrons of an atom. Which of the transitions will produce the emission of longest wavelength ?
Which of the transitions will produce the emission of highest frequency?
The following statements relate to atomic spectrum.
I. All elements emit and absorb characteristic spectra
II. Spectral analysis is an important method of identifying environmental pollutants
III. The chemical composition of stars could be determined using spectral analysis . Which of the statements above are correct?
I,II and III
II and III only
I and III only
I and II only
In an operating X-ray tube, a high p.d is applied between the cathode and the anode for the purpose of
heating the cathode
producing a stream of electrons
concentrating electrons on the target
accelerating the electrons to a very high energy
heating the anode
An evidence of the particle nature of matter is the
In 90 seconds, the mass of a radioactive element reduces to 1/32 of its original value. Determine the half-life of the element .
The half-life of a radioactive source is 1 minute. If a ratemeter connected to the source registers 200µA at a given time , what would be its reading after 3 minutes ?
A spring of natural length 25cm, when loaded in air, and then in water, extends to 30cm and 28cm respectively. Calculate the relative density of the load.
Answer: EAtomic and Nuclear Physics