Atomic and Nuclear Physics Generix Content - Atomic and Nuclear Physics
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WAEC questions for "Physics :: Atomic and Nuclear Physics"
Q1

Calculate the first excitation energy of the atom.

A

1.60 x 10-19 J

B

1.02 x 10-18 J

C

1.60 x 10-18 J

D

1.02 x 10 j

E
Q2

If the atom de-excites from n=2, the wavelength of the emmited radiation is

A

2.4 x 10-7 m

B

1.2 x 10-7 m

C

2.4 x 10-9 m

D

1.2 x 10-9 m

E
Q3

Two isotopes of uranium are designated as 238 U and 235 U . The 238 and 235 represent their

A

atomic numbers

B

nucleon numbers

C

proton numbers

D

neutron numbers

E
Q4

The main difference between x-rays and y-rays lies in their

A

ionizing ability

B

absorption rate

C

mode of production

D

mode of propagation

E
Q5

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]

A

9.10 x 10-24 m

B

4.55 x 10-17 m

C

7.25 x 10-11 m

D

6.20 x 10-8 m

E
Q6

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?

A

I only

B

II only

C

III only

D

I and III only

E
Q7

When a radioactive substance undergoes a beta decay, its

A

mass number decreases  by 1

B

atomic number decreases by 1

C

mass number increases by 1

D

atomic number increases by 1

E
Q8

Nuclear fission is preferred to nuclear fusion in the generation of energy because

A

very high temperature s are required for fusion

B

the raw materials for fusion are easily obtained

C

energy obtained from fusion is relatively smaller

D

the by products of fusion are very dangerous

E
Q9

Control in nuclear reactors is effected with boron rods because the rods have ability to

A

absorb electrons

B

absorb neutrons

C

accelerate electrons

D

slow down neutrons

E
Q10

A  radioactive elements has a decay constant  of 0.777s-1 calculate its half-life

A

13.0s

B

9.0s

C

5.1s

D

0.5s

E
Q11

Which of the following electromagnetic waves can be detected by its heating effect?

A

B

X-rays

C

Gamma rays

D

E
Q12

If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer

A

an explosion s observed

B

the rainbow colours are seen

C

an emission spectrum is observed

D

dark lines are observed

E
Q13

The number of protons in an element increased by one after radioactive decay. The element must have decayed by emitting

A

a beta particle

B

an alpha particle

C

a gamma ray

D

a neutron

E
Q14

The correct sequence of energy transformations in the operation of an X-ray tube is

I. X-rays

II. Kinetic energy of thermo electrons

III. Potential energy of the target atoms

IV. Heat energy of the emitted electrons

A

IV, III, II,I

B

IV, II, III

C

II, IV, III, I

D

III, IV,II,I

E
Q15

In a nuclear reactor, chain reactions result from the release of

A

electrons

B

photons

C

neutrons

D

protons

E
Q16

The breaking up of an atomic nucleus into two fragments of nearly equal sizes is known as

A

nuclear fusion

B

nuclear fission

C

thermonuclear reaction

D

E
Q17

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]

A

4.2 x 105 ms-1

B

1.8 X 108 ms-1

C

4.2 x 105 ms-1

D

1.8 x 105 ms-1

E
Q18

A radioactive substance of mass 768g has a half life of 3 years. After how many years does this substance leave only 6g undecayed ?

A

21

B

18

C

15

D

12

E
Q19

Fusion is not usually used for generating electric power because

A

no energy is released when fusion takes place

B

very high temperatures are required to initiate  fusion reaction

C

the raw materials needed are not easily available

D

heavy nuclei are involved

E
Q20

An atom 234/91 P emits  a gamma radiation. The resultant nuclide is

A

234/90 Th

B

234/89Ac

C

230/90 Th

D

234/91 Pa

E
Q21

Which of the following statements is an advantage of nuclear fusion over nuclear fission?

A

The resulting chain reaction which produces large amount of energy

B

No radioacvtive waste is produced as by-product

C

Very high temperatures required in the process

D

E
Q22

Beta particles are fast-moving

A

protons

B

electrons

C

neutrons

D

photons

E
Q23

A process by which two light atoms join to form a new atom of higher atomic mass is

A

B

nuclear fission

C

nuclear fusion

D

chain reaction

E
Q24

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]

A

1.7V

B

2.0V

C

8.0V

D

15.0V

E
Q25

In which of the following devices is the principle of photoeletric effect not applicable?

A

Closed-circuit television camera

B

Burglar alarm

C

Solar cells

D

Periscope

E
Q26

Which of the following statements about X-rays is not correct? They

A

are electromagnetic waves

B

can be used to study crystal lattice

C

can destroy living cells

D

are produced from the nucleus of an atom

E
Q27

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.

A

49.6g

B

37.2g

C

24.8 g

D

12.4 g

E
Q28

Which of the following representations is correct for an atom X with 28 electrons and 30 neutrons ?

A

30 x

28

B

28 X

30

C

58 X

30

D

58 X

28

E
Q29

Which of the following statements is true of ultra violet radiations? It

A

supports the sensation of hearing

B

does not cause the emission of electrons from metals

C

is an electromagnetic wave

D

is not capable of causing sun bum

E
Q30

Which of the following statements is not true of the isotopes of an element? They

A

are atoms of the same element

B

have the same chemical properties

C

have the same atomic number

D

have the same mass number

E
Q31

A radioactive element has a decay constant of 0.077 s-1 calculate its half life

A

12.5s

B

9.0s

C

5.1 s

D

0.5s

E
Q32

The minimum energy required to remove an electron from an atom is known as

A

excitation energy

B

ionizaion energy

C

binding energy

D

photon energy

E
Q33

Nuclear fussion is preferred to nuclear fussion in the generation of energy because

A

very high temperatures are equired for fussion

B

the raw materials for fussion are not easily obtained

C

energy obtained from fussion is relatively smaller

D

the byproduct of fussion are very dangerous

E
Q34

Which of the following reactions represents nuclear fussion?

A

2/1H +  2/1 H    - 2/3He  + 1/0n

B

235/92 U + 1/0 n→145/56 Ba + 90/36Kr + 2 1/0 r

C

234/90  Th  →    1/0 n  +   234/94 Pa

D

U 288/924/2 He + 234/90 Th

E
Q35

In a model of the hydrogen atom, the energy levels atom, the energy levels Wn are given by the formula W= 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

A

R

5

B

-R

4

C

5R

36

D

-5R

36

E
Q36

If a radioactive atom emits a beta  particle, its mass number

A

increases by one

B

remains the same

C

decreases by one

D

increases by two

E
Q37

When the light falls on a metallic surface, the number of electrons that may be emitted would depend solely on the

A

area of the metalic surface

B

frequency of the light

C

intensity of the light

D

time of exposure of the metalic surface to light

E
Q38

Which of the following materials is used to control the rate of neutron production in a nuclear reactor?

A

Boron rods

B

Concrete shield

C

Graphite rods

D

Uranium rods

E
Q39

Which of the following is usually used to cause fission in an atomic reactor?

A

Alpha particles

B

Beta particles

C

Electrons

D

Neutrons

E
Q40

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

A

12 and 6

B

14 and 7

C

16 and 8

D

19 and 8

E
Q41

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]

A

n=2 to n=1

B

n=1 to n=2

C

n=2 to n=3

D

n=3 to n=2

E
Q42

Production of x-rays in an x-ray tube begins with

A

photo electric emission

B

collision of electrons

C

thermionic emission

D

field emission of electrons

E
Q43

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

11

B

12

C

23

D

34

E
Q44

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?

A

The bombardment results into nucleus with greater proton number

B

It is an induced nuclear reaction

C

It is a natural radioactive decay

D

The sum of the initial nucleon numbers is equal to the sum of the final nucleon numbers

E
Q45

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.

A

II, IV,I and II

B

I,II, III and IV

C

III, I, IV

D

IV, I, III and II

E
Q46

Electrons passing through crystals are diffracted because they

A

are repelled by atoms in the cystals

B

are attracted by the atoms in the cystal

C

posses wave properties

D

are particles

E
Q47

The duality of matter implies that matter

A

exists as a particle of dual composition

B

has momentum and energy

C

has both wave and particle properties

D

is made up of dual materials

E
Q48

A nuclide Y emits in succession an α-particle and a β- particle. the atomic number of the resulting nuclide is

A

198

B

83

C

82

D

80

E
Q49

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

84 days

B

70 days

C

56 days

D

40 days

E
Q50

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]

A

1.8 x 1020 J

B

1.8 x 1013 J

C

1.8 x 1011 J

D

1.8 x 1010 J

E
Q51

Absorption line spectra exhibited by atoms is a result of

A

change in kinetic energy of a moving atom

B

instability of the nucleons

C

excitation of an electron in the atom

D

transition of an electron from a higher to a lower energy level

E
Q52

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?

A

I only

B

II only

C

I and II only

D

I and III only

E
Q53

The diagram illustrates the energy trasitions of five electrons of an atom. Which of the transitions will produce the emission of longest wavelength ?

A

I

B

II

C

III

D

IV

E
Q54

Which of the transitions will produce the emission of highest frequency?

A

V

B

IV

C

III

D

II

E
Q55

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?

A

I,II and III

B

II and III only

C

I and III only

D

I and II only

E
Q56

In an operating X-ray tube, a high p.d is applied between the cathode and the anode for the purpose of

A

heating the cathode

B

producing a stream of electrons

C

concentrating electrons on the target

D

accelerating the electrons to a very high energy

E

heating the anode

Q57

An evidence of the particle nature of matter is the

A

orbital motion

B

brownian motion

C

rotational motion

D

traslational motion

E
Q58

In 90 seconds, the mass of a radioactive element reduces to 1/32 of its original value. Determine the half-life of the element .

A

45s

B

36s

C

18s

D

16s

E

9s

Q59

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

100.0µA

B

66.7µA

C

50.0µA

D

25.0µA

E

12.5µA

Q60

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.

A

2.5

B

1.7

C

1.5

D

0.7

E

0.6