PPSC Chemistry Lecturer Preparation (Test # 03)- Malik Xufyan

Malik Xufyan WhatsApp # 0313-7355727
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PPSC CHEMISTRY CLASS
Test Session
CH: Nuclear Chemistry
Test # 03
For more WhatsApp # 0313-7355727
Topics:
1. Radioactivity
2. Detection and measurement of radioactivity
3. Kinetics of radioactive decay
4. Nuclear fission
5. Nuclear fusion
Radioactivity
1. The nucleus of radioactive element possesses
(a) Low binding energy
(b) High binding energy
(c) Zero binding energy
(d) High potential energy
2. Nuclear energy is based on the conversion of
(a) Protons into neutrons
(b) Mass into energy
(c) Neutrons into protons
(d) Uranium into radium
3. Positron has nearly the same weight as that of
(a) Alpha-particle
(b) Proton
(c) Neutron
(d) Electron
4. A nuclear reaction must be balanced in terms of
(a) Only energy

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(b) Only mass
(c) Mass and energy
(d) None of these
5. The introduction of a neutron into the nuclear composition of an atomwould lead to a
change in
(a) The number of the electrons also
(b) The chemical nature of the atom
(c) Its atomic number
(d) Its atomic weight
6. Neutrino has
(a) Charge +1, mass 1
(b) Charge 0, mass 0
(c) Charge – 1, mass 1
(d) Charge 0 , mass 1
7. Formation of nucleus from its nucleons is accompanied by
(a) Decrease in mass
(b) Increase in mass
(c) No change of mass
(d) None of them
8. The nucleus of an atom is made up of X protons and Y neutrons. Forthe most stable
and abundant nuclei
(a) X and Y are both even
(b) X and Y are both odd
(c) X is even and Y is odd
(d) X is odd and Y is even
9. How many neutrons are present in the nucleus of Ra
(a) 88
(b) 226
(c) 140
(d) 138
10. Which of the following is the heaviest metal
(a) Hg
(b) Pb
(c) Ra

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(d) U
11. The a-particle is identical with
(a) Helium nucleus
(b) Hydrogen nucleus
(c) Electron
(d) Proton
12. Radioactivity is due to
(a) Stable electronic configuration
(b) Unstable electronic configuration
(c) Stable nucleus
(d) Unstable nucleus
13. Radioactive disintegration differs from a chemical change in being
(a) An exothermic change
(b) A spontaneous process
(c) A nuclear process
(d) A unimolecular first order reaction
14. When a radioactive element emits an electron the daughter elementformed will have
(a) Mass number one unit less
(b) Atomic number one unit less
(c) Mass number one unit more
(d) Atomic number one unit more
15. During a b--decay the mass of the atomic nucleus
(a) Decreases by one unit
(b) Increases by one unit
(c) Decreases by two units
(d) Remains unaffected
Detection and Measuement
16. Which of the following acts as ionising gas in Geiger Muller (G.M.) counter?
(a) Alcohol
(b) Argon gas
(c) Krypton
(d) Hydrogen
17. Which of the following is not a type of radiation detector?

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(a) Geiger Muller (G.M.) counter
(b) Proportional counter
(c) Semiconductor radiation detector
(d) Flame emission detector
18. ‘When nuclear radiations pass through the counter, gas ionization is produced.’
This is the principle of which of the following detectors?
(a) Proportional counter
(b) Flow counter
(c) Geiger Muller counter
(d) Scintillation counter
19. Which of the following acts as quenching gas in G.M. counter?
(a) Alcohol
(b) Argon gas
(c) Krypton
(d) Hydrogen
20. Which of the detectors is similar to G.M. counter in construction but is filled
with heavier gas?
(a) Proportional counter
(b) Strip detector
(c) Semiconductor detector
(d) Scintillation counter
21. Which of the following gases are used in proportional counter as the ionising
gas?
(a) Alcohol
(b) Neon gas
(c) Krypton
(d) Heavy water
22. Which of the following is the main disadvantage of solid state semiconductor
radiation detector?
(a) Low accuracy
(b) Low sensitivity
(c) It should be maintained at low temperature
(d) High avalanche breakdown voltage
23. Scintillation detector is a large flat crystal of which of the following materials?

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(a) Sodium chloride
(b) Sodium iodide
(c) Sodium sulphate
(d) Sodium carbonate
24. When X-ray enters the solid state (Si) detector it produces ion pair rather than
electron-hole (e-h) pair.
(a) True
(b) False
25. Which of the following materials are used as the insulation between inner and
outer electrodes of the ion chamber?
(a) Ceramic
(b) Plastic
(c) Polytetrafluoroethylene
(d) Polyacrylamide
26. Gaseous compounds containing radioactive sources can be directly introduced
into the ionization chamber.
(a) True
(b) False
27. Liquid Scintillators are used for which of the following materials?
(a) Low energy beta materials
(b) High energy beta material
(c) Low energy gamma materials
(d) Fast neutron
Kinetics of radioactive decay
28. Radioactive decay is a
(a) First order reaction
(b) Second order reaction
(c) Third order reaction
(d) Zero order reaction
29. Activation energy of any radioactive decay process is:
(a) 1
(b) 2

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(c) 3
(d) 0
30. The half-life period of a radioactive substance is best determined by counting the
number of alpha particles emitted per second in a Geiger Muller counter from its
known quantity. If the half-life period of a radioactive substance is one month, then?
(a) it will completely disintegrate in two months
(b) l/8th of it will remain intact at the end of four months
(c) 3/4th of it will disintegrate in two months
(d) it will completely disintegrate in four months
31. A certain nuclide has a half-life period of 30 minutes. If a sample containing 600 at-
oms is allowed to decay for 90 minutes, how manyatoms will remain
(a) 200 atoms
(b) 450 atoms
(c) 75 atoms
(d) 500 atoms
32. If the quantity of a radioactive element is doubled, then its rate of disintegration per
unit time will be
(a) Unchanged
(b) Reduced to half
(c) Increased by root2 times
(d) Doubled
33. Half-life period of a metal is 20 days. What fraction of metal does remain after 80
days
(a) 1
(b) 1/16
(c) 1/4
(d) 1/8
34. A radioactive element decays at such a rate that after 15 minutesonly 1/10 of the
original amount is left. How many more minutes will be needed when only 1/100 of the
original amount will be left
(a) 1.5 minutes
(b) 15.0 mintues
(c) 16.5 minutes
(d) 30 minutes

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35. A radioactive isotope having a half-life of 3 days was received after12 days. It was
found that there were 3 gm of the isotope in the container. The initial weight of the iso-
tope when packed was
(a) 12 gm (b) 24 gm
(c) 36 gm (d) 48 gm
36. The half-life of a radioactive element is 6 months. The time taken to reduce its origi-
nal concentration to its 1/16 value is
(a) 1 year
(b) 16 years
(c) 2 years
(d) 8 years
37. Strontium-85, used for bone scans, has a half-life of 65 days. How long will it take
for the radiation level of Strontium-85 to drop to one-fourth of its original level.
(a) 65 days
(b) 130 days
(c) 195 days
(d) 260 days
38. The half-life of bromine-74 is 25 min. How much of a 4.0 mg sample is still active
after 75 min?
(a) 0.50 mg
(b) 1.0 mg
(c) 2.0 mg
(d) 0.25 mg
39. Krypton-79 has a half-life of 35 hours. How many half-lives have passed after 105
hours?
(a) 1 half-life
(b) 2 half-lives
(c) 3 half-lives
(d) 4 half-lives
40.The activity of a radioisotope is defined as:
(a) the radiation absorbed by a gram of material
(b) the biological effect of different kinds of radiation
(c) the amount of radiation absorbed by a material
(d) the number of disintegrations per second

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Nuclear fission
41. Who invented nuclear fission?
(a) Rutherford
(b) Hans Bethe
(c) Otto Hahn
(d) Marie Curie
42. When a target nucleus is bombarded by an appropriate beam of particles, it is pos-
sible to produce
(a) a less massive nucleus, but not a more massive one.
(b) a more massive nucleus, but not a less massive one.
(c) a nucleus with smaller atomic number, but not one with a greater
atomic number.
(d) a nucleus with greater atomic number, but not one with a smaller atomic number.
(e) a nucleus with either greater or smaller atomic number.
43. What is the meaning of the term "critical mass"?
(a) This refers to the mass of the "critical" elements in a reactor, i.e., the
uranium or plutonium.
(b) This refers to the minimum amount of fissionable material required to sustain a chain re-
action.
(c) This is the amount of mass needed to make a power reactor economically
feasible.
(d) This is the material which is just on the verge of becoming radioactive.
44. When lead-207 (Z = 82) is bombarded with neutrons, it can change into
(a) lead-208
(b) lead-206
(c) tellurium-208 (Z = 81)
(d) bismuth-208 (Z = 83)
45. Complete the following nuclear reaction:
16O + 4He -> ___ + 19Ne
8 2 10
(a) 1p
(b) 1n

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(c) 2H
(d) 3H
46. What is the energy released (positive) or absorbed (negative) in the following reac-
tion?
3H + 3H = 4He + 2(1n)
(3.016049) (3.016049) (4.002603) (1.008665)
(a) 0.0122 MeV
(b) -0.0122 MeV
(c) 11.3 MeV
(d) -11.3 MeV
47. The fuel for nuclear fusion in the center of the Sun is
(a) H
(b) He
(c) U
(d) any radioactive material
48. What is the mass of the products of a nuclear fission reaction compared to the mass
of the original products?
(a) greater
(b) less
(c) the same
(d) varies according to the reaction
49. What is the mass of the products of a nuclear fusion reaction compared to the origi-
nal elements?
(a) greater
(b) less
(c) the same
(d) varies according to the reaction
50. The fuel for nuclear fission is
(a) H
(b) He
(c) U
(d) any radioactive material
51. All of the following are units used to describe radiation dosage in humans except

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(a) curie.
(b) rad.
(c) rem.
(d) RBE.
52. A unit that measures the effective dose of radiation in a human is the
(a) curie.
(b) rad.
(c) rem.
(d) RBE.
53.The chief hazard of radiation is
(a) damage to living cells due to ionization.
(b) damage to cells due to heating.
(c) damage to living cells due to the creation of chemical impurities.
(d) the creation of new isotopes within the body.
54. An X-ray technician takes an avearge of ten X-rays per day and receives 2.5 mrad
per X-ray. What is the total dose the technician receives in 250 working days?
(a) 2.50 rem
(b) 5.00 rem
(c) 6.25 rem
(d) 7.75 rem
Nuclear fusion
55. The fusion reaction takes place under ________
(a) High Temperature and Low Pressure
(b) Low Temperature and High Pressure
(c) High Temperature and High Pressure
(d) Low Temperature and Low Pressure
56. Which process happens inside a star?
(a) Electron Excitation
(b) Nuclear fusion
(c) Nuclear fission
(d) Diffusion

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57. What would be the effect of a nuclear holocaust?
(a) Nuclear Summer
(b) Nuclear Spring
(c) Nuclear Autumn
(d) Nuclear Winter
58. Nuclear fusion is the phenomenon of ___________
(a) Heavy nucleus splitting
(b) Heavy nuclei combining
(c) Light nucleus splitting
(d) Light nuclei combining
59. How many number of nuclei of hydrogen fuse in a series of reaction involving other
particles that continually appear and disappear?
(a) 1
(b) 2
(c) 3
(d) 4
60. Fusion reactions are called __________
(a) Thermonuclear
(b) Thermoduric
(c) Thermo Uric
(d) Compound reactions
61. In the Sun, nuclei of hydrogen combine to form a larger nucleus and release a great
amount of energy. The process is known as
(a) fission.
(b) fusion.
(c) metathesis.
(d) chain reaction.
62. Why is it necessary to accelerate positively charged nuclei to high kinetic energies to
cause fusion?
(a) To overcome electrical repulsive forces
(b) To result in high amount of energy in short period of time
(c) To get the isobars and isotopes
(d) To get a sustainable reaction

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63. Which of the following element is readily available in the ordinary water?
(a) Cesium
(b) Thorium
(c) Deuterium
(d) Astatine
64. Fusion energy is higher than fission energy.
(a) True
(b) False
65. The energy released in the process of hydrogen bomb is almost _____times higher
than atomic bomb.
(a) 100
(b) 1000
(c) 10000
(d) None

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